the genus porpidia in northern and western europe,...

The Lichenologist 37(1): 1–35 (2005) � 2005 The British Lichen SocietyDOI: 10.1017/S0024282904014628 Printed in the United Kingdom

The genus Porpidia in northern and western Europe, with specialemphasis on collections from the British Isles

Alan M. FRYDAY

Abstract: Four new species and one new forma are described in the genus Porpidia. Porpidiaflavocruenta Fryday & Buschbom, a member of the P. macrocarpa group that has previously beenoverlooked for ‘P. flavocoerulescens’, is reported from Austria, the British Isles, Scandinavia, Iceland,and North America (Alaska); P. islandica Fryday, Knoph & Hertel is reported from Iceland andScotland; and P. pachythallina Fryday and P. striata Fryday from the British Isles only. The sorediatemorph of P. superba is described as P. superba f. sorediata Fryday, known from the British Isles,Sweden, Svalbard, and North America (Maine). Variation in P. macrocarpa is discussed and the newcombination P. macrocarpa f. nigrocruenta (Anzi) Fryday made. Secondary metabolite production isdiscussed and the variation in the production of chemosyndromes considered to be more variablethan previously reported. The position of several other taxa is discussed and P. herteliana andP. musiva are reduced to synonymy with P. cinereoatra, P. calcarea to synonymy with P. superba, andP. diversa to synonymy with P. contraponenda. However, P. grisea and P. lowiana are provisionallymaintained as distinct species from P. tuberculosa and P. cinereoatra respectively, although P. grisea hasnot been correctly recorded from the British Isles. The typification of Spiloma tuberculosa Sm., thebasionym of Porpidia tuberculosa, is discussed and a lectotype proposed; the new combination Porpidiarugosa (Taylor) Coppins & Fryday is made and shown to be the correct name for P. glaucophaea; andPorpidia flavicunda (Ach.) Gowan is used for the esorediate taxon usually known as Porpidiaflavocoerulescens because this epithet is to be proposed for rejection as it is considered to be ofconfused usage. Porpidia hydrophila is shown to be a member of the P. albocaerulescens group. Porpidialowiana, P. nadvornikiana, and P. thomsonii are recorded for the first time from the British Isles, andP. macrocarpa f. nigrocruenta confirmed as a British taxon. Notes and a key are provided for all thespecies of the genus that have been reported from the area.

Key words: Central Europe, North America, Porpidiaceae, saxicolous lichens

Introduction

The genus Porpidia was erected by Körber(1855) to accommodate the single speciesP. trullisata (Kremp.) Körb. It was resur-rected by Hertel (1984) as the correct namefor the genus Huilia Zahlbr. that the sameauthor (Hertel 1975) had previously segre-gated from the large, artificial genus LecideaAch. Porpidia is a cosmopolitan genus ofobligate saxicolous species that is abundantin mountainous regions and other areaswhere non-vegetated rock surfaces are com-mon. The species occur mostly on siliceous

rocks, although a few are confined to base-rich rocks, and isolated occurrences on bark,lignum, worked timber and consolidated soilhave been noted (Inoue 1983; A. M. Frydayunpublished data). The genus is one of themost studied of the segregates of Lecidea(e.g. Hertel 1975, 1977; Inoue 1983; Hertel& Knoph 1984; Knoph 1984; Schwab 1986;Gowan 1989a, b, and unpublished; Gowan& Ahti 1993; Buschbom & Mueller 2004;J. Buschbom unpublished), but in spite ofthis, and even though specimens of thegenus are probably more frequent than thoseof any other saxicolous genus in mountain-ous areas, the species of the genus are stillpoorly understood.

The reasons for this are largely because ofthe difficulty in recognizing species-level

Alan M. Fryday: Herbarium, Department of PlantBiology, Michigan State University, East Lansing,MI 48824—1312, USA.

characters within the genus. Most species ofPorpidia have a grey thallus and black sessileapothecia and, as macroscopic characters(e.g. thickness of thallus, size of apothecia)appear to be extremely variable within asingle species, specimens are usually imposs-ible to identify beyond genus in the field.Consequently, they are rarely collected and,in floristic studies, are usually lumped undernames such as P. crustulata (Ach.) Hertel &Knoph or P. macrocarpa (DC.) Hertel &A. J. Schwab. Many of the characters used toseparate the species are cryptic (e.g. chem-istry, structure of the exciple) and revealedonly after detailed microscopic/chemicalinvestigation. Even then it is still oftenimpossible to assign a collection to a specieswith any degree of certainty. This low like-lihood of a positive identification also con-tributes to the genus being poorly collected.However, recent molecular studies ofthe genus (Buschbom & Mueller 2004;J. Buschbom unpublished) have greatlyenhanced our understanding of the infra-generic relationships, thus permitting are-assessment of morphological charactersthat should result in a clearer understandingof species concepts within the genus.

In spite of their abundance, the number ofspecies in the genus is low, probably, at leastin part, because they are poorly collected.The most recent checklist of British lichens(Coppins 2002) lists only 17 taxa, comparedwith, for example, 41 in RhizocarponRamond ex DC. and 25 in Lecidea Ach. s.str., the two other most frequent saxicolousgenera. However, extensive field workconcentrating on the saxicolous lichen veg-etation of the British mountains over thepast two decades (e.g. Fryday 1996a,1997a, b, 2001a, b, 2002a, b; Gilbert &Coppins 1992; Gilbert & Fox 1985, 1986;Gilbert & Fryday 1996; Gilbert & Giavarini1993; Gilbert et al. 1982, 1988, 1992) hasrevealed a number of well-characterized,apparently undescribed entities within thegenus. Five of these are described here asnew taxa, whereas others still await formalrecognition, and many other collections can-not currently be accommodated within anytaxonomic grouping. In addition, P. lowiana

Gowan, P. nadvornikiana (Vezda) Hertel,and P. thomsonii Gowan are here reportedfor the first time from the British Isles, andP. macrocarpa f. nigrocruenta (Anzi) Frydayconfirmed as a British taxon. However, twospecies included by Coppins (2002) are ex-cluded; P. grisea Gowan has been incorrectlyreported from the British Isles, and P.musiva (Körb.) Hertel & Knoph is shown tobe a synonym of P. cinereoatra.

Materials and MethodsObservations are based on material collected by theauthor from the British Isles and specimens held in BM,CANL, E, F, MICH, MIN, MSC, WIS and thepersonal herbarium of J. Buschbom. All specimenscollected by the author are held in his personalherbarium unless otherwise noted.

Microscopic descriptions are based on observationsmade on hand-cut sections mounted in water and 10%KOH. All anatomical measurements were made in10% KOH and all ascospore measurements excludeperispore.

Thin-layer chromatography (TLC) follows themethods of White & James (1985). Rf values for com-pounds present in Porpidia species are given by Gowan1989b. Confluentic acid was tested for using themethod described by Fryday (1991), in which a sectionof thallus or apothecium on a microscope slide isflooded with 10% KOH and viewed under a compoundmicroscope (�40 objective). If confluentic acid ispresent the section becomes surrounded by a ‘halo’ ofsmall oil-droplets (or bubbles) that issue from thesection.

Nomenclature for epihymenial pigments followsMeyer & Printzen (2000), with the addition of the nameMacrocarpa-green (Fryday 2002b).

In this study, the taxa are arranged in accordancewith the three infrageneric groupings identified byBuschbom & Mueller (2004), which will probablyrequire recognition at the generic level (Table 1). Amore complete synonymy for many of the species listedhere is given by Schwab (1986) and Gowan & Ahti(1993).

Infrageneric grouping within Porpidia

The analyses of Buschbom and Mueller(2004) indicated that the genus Porpidiacould be divided into three infra-genericgroups (Table 1), with a high probabilitythat the Lecideaceae s. str. (i.e. Lecidea andCecidonia) was nested within them (Fig. 1).This suggested that either the Porpidiaceaeshould be included within the Lecideaceae

2 THE LICHENOLOGIST Vol. 37

(and Porpidia within Lecidea), or that Por-pidia should be divided into at least three,and possibly four, separate genera. How-ever, because Buschbom and Muellerstudied only a limited number of the relevanttaxa, and because of the lack of consistentsupporting morphological/chemical differ-ences, they preferred to await the results offurther analyses of all the available charactersystems (molecular, morphological, andchemical) before making any taxonomicinnovations.

The three groups identified by Buschbom& Mueller (2004) were:

The P. macrocarpa group (divided intothe macrocarpa and cinereoatra subgroups).This group is characterized by thick excipu-lar hyphae (Gowan 1989a: fig. 12) and asecondary metabolite chemistry of thestictic/norstictic acid chemosyndrome orno substances (macrocarpa subgroup), orthe confluentic acid or methyl 2#-O-

methylmicrophyllinate chemosyndromes(cinereoatra subgroup). The cinereoatra sub-group appears to be a sister group, andclosely related, to Amygdalaria Norman andalso differs from the macrocarpa subgroup inhaving a more uniformly dark pigmentedexciple. If the two subgroups are consideredtogether then they should possibly be trans-ferred to Amygdalaria. However if they areconsidered as separate, then the cinereoatrasubgroup could be transferred to Amy-gdalaria, and the name Haplocarpon M.Choisy is available for the macrocarpasubgroup.

The P. albocaerulescens group. Thisgroup is characterized by its distinctiveexciple structure with thin, filamentousexcipular hyphae, and a dark pigmentedcortex with an unpigmented medulla(Gowan 1989a: fig. 9). This group has avaried chemistry; species containing the stic-tic acid, or 2#-O-methylsuperphyllinic acid

T 1. Arrangement of species of Porpidia among three major infrageneric groups (after Buschbom & Mueller 2004).Species in roman characters are treated as synonyms in this study

Porpidia macrocarpa group Porpidia speirea group Porpidia albocaerulescens group

macrocarpa subgroup speirea subgroup P. albocaerulescens‡P. crustulata P. grisea P. rugosa (syn. P. glaucophaea)P. flavocruenta† P. speirea P. hydrophila*P. herteliana* P. tuberculosaP. islandica* flavicunda subgroupP. macrocarpa P. flavicunda (syn. P. flavocoerulescens)P. macrocarpa f. nigrocruenta* P. melinodesP. nadvornikiana*P. ochrolemmaP. platycarpoides*P. soredizoidesP. striata*P. superbaP. superba f. sorediata*P. thomsonii*P. zeoroides

cinereoatra subgroupP. cinereoatraP. contraponendaP. diversaP. musiva*P. lowianaP. pachythallina*

*Not studied by Buschbom & Mueller (2004).†Porpidia sp. 2 & P. nigrocruenta sensu Buschbom & Mueller 2004.‡Not correctly recorded from NW Europe.

2005 Porpidia—Fryday 3

(but not the confluentic) chemosyndromesor no substances. There is apparently noavailable name for this group if it is recog-nised at the genus level.

The P. speirea group (divided into thespeirea and flavicunda subgroups). Thisgroup is characterized by having thinnerexcipular hyphae than the P. macrocarpagroup but without the sharp contrast inpigmentation between the dark margin andthe hyaline medulla of the exciple that ischaracteristic of the P. albocaerulescensgroup. They also differ from the P. albo-caerulescens group chemically; all the speciesof the P. speirea group having the confluenticchemosyndrome as their primary chemo-type. Two subgroups can be recognized;members of the speirea subgroup having awhite or grey thallus with an amyloid (I+)medulla and a poorly developed exciple witha pale medulla, whereas those of the flavi-cunda subgroup have an obligate orangethallus with a non-amyloid (I�) medullaand a well developed exciple with a moredarkly pigmented medulla.

As Körber (1855) erected the genus Por-pidia for the single species P. trullisata(Kremp.) Körb., this is, consequently, thetype species of the genus. Unfortunately P.trullisata is known only from Central Europe

and is rarely collected, so fresh material wasnot available for study by Buschbom &Mueller and it was not included in theiranalyses (Buschbom & Mueller 2004). Con-sequently, it is impossible to say with cer-tainty which of the three groups identified byBuschbom & Mueller is Porpidia s. str. How-ever, P. trullisata has an amyloid (I+ blue)medulla, which is known to occur only in thespeirea subgroup of the P. speirea group andit also appears to be morphologically closelyrelated to P. speirea (Ach.) Kremp. and bothspecies also occur on base-rich rock. How-ever, P. trullisata differs from P. speirea incontaining stictic rather than confluenticacid (although P. speirea does occasionallycontain stictic acid in addition to confluenticacid), and stictic acid is rare in the P. speireagroup. Therefore, although P. trullisataprobably belongs in the P. speirea group,which is consequently Porpidia s. str., thisrequires confirmation.

The Porpidia macrocarpa group

Porpidia cinereoatra (Ach.) Hertel &Knoph

In Hertel, Beih. Nova Hedwigia 79: 437 (1984).—Lecidea cinereoatra Ach., Lich. Univ.: 167 (1810); type:

F. 1. Simplified phylogenetic arrangement of infrageneric groups of Porpidia (after Buschbom & Mueller 2004).


East Germany, Lausitz, Mosig 52 (H-ACH 100—lectotype!).

Porpidia herteliana Gowan syn. nov., Bryologist 92: 48(1989); type: USA, Michigan, Keweenaw Co., IsleRoyale National Park, Wetmore 52815 (MIN—holotype!).

Porpidia musiva (Körb.) Hertel & Knoph syn. nov., inHertel, Beih. Nova Hedwigia 79: 438 (1984).—Lecideamusiva Körb., Parerga Lich.: 220 (1861); type:Germany (L—holotype!).

Porpidia cinereoatra is characterized by hav-ing a thallus containing confluentic acid,innate apothecia with richly branched andanastomosing, conglutinate paraphyses, anda dark exciple. It closely resembles P. con-traponenda and the separation of P. ciner-eoatra from P. contraponenda is discussedunder that species. Gowan (1989a) adopteda narrow species concept in this group,reserving the name P. cinereoatra for speci-mens with a thick thallus, innate, pruinoseapothecia, and an Appalachian–Great Lakesdistribution in North America; introducingthe new species P. herteliana for specimenswith non-pruinose apothecia and a similardistribution to P. cinereoatra, and P. lowianafor specimens with a thinner thallus, sessileapothecia and an arctic distribution.

The collections in MIN, CANL and WISreferred by Gowan (1989a) to P. hertelianaare very mixed in gross morphology. Thethallus can be thick and white to thin andmedium grey, whereas apothecia are im-mersed or sessile and pruinose or not, with acomplete range of intermediates. The apoth-ecial anatomy is similarly variable andGowan herself recognizes the variation in thepigmentation of the exciple. The protologueof P. herteliana describes the species as‘‘Thallus light olive grey to light greenish oryellowish grey’’ and ‘‘Apothecia . . . soonbecoming sessile’’. Unfortunately, the col-lection designated as the holotype of P.herteliana (MIN) bears little resemblance tothe protologue, having a thick white thallusand innate apothecia, and is clearly referableto P. cinereoatra in both morphology andapothecial anatomy. Consequently, P.herteliana is here reduced to synonymy withP. cinereoatra. However, there is at least onedistinct entity among these collections thatdiffers from P. cinereoatra in both gross mor-

phology and apothecial anatomy, and moreaccurately matches the protologue. Thisentity, which has a thin green-grey thallusand sessile, non-pruinose apothecia, has alsobeen recorded from the British Isles, butfurther work is required to characterize itfully. It is possible that other distinct taxawill also be separated from P. cinereoatra but,currently, I prefer to retain them all in thatspecies. Porpidia lowiana, however, is hereconsidered to be a distinct species and isdiscussed in detail below.

Gowan & Ahti (1993) accepted Porpidiamusiva as a distinct species, separating itfrom P. cinereoatra by its thicker, wartedthallus and larger ascospores. Gowan(1989a) reports ascospore dimensions forP. cinereoatra as 13–13·6–18�6–6·6–9 �m,and even smaller for P. herteliana and P.lowiana. However, investigation of the holo-types of P. herteliana and P. lowiana, anisotype of P. cinereoatra and material ident-ified as these species by Gowan, revealed theascospores to be significantly larger, (15–)18–20(–22)�(7–)8–9 �m. This is similar tothat reported by Inoue (1983) for P. musiva(15–20�8–10 �m) and confirmed by ex-amination of the holotype of that species. Itis my opinion that, as suggested by Galloway& Coppins (1992), P. musiva is a variant ofP. cinereoatra with an unusually thick thallusand should be reduced to synonymy with it.An even more extreme (unnamed) variant ofP. cinereoatra, with a thick creamy-whitethallus and innate non-pruinose apothecia,is known from the Scottish Highlands. Itis particularly frequent in the base-richBreadalbane Mountains.

Selected specimens examined. Great Britain: Wales:V.C. 46, Cardiganshire (Ceridigion): Devil’s Bridge,Bodcoll, 23/758768, 250 m, block spoil from mine,1994, Fryday (5031) & S. P. Chambers. V.C. 49Caernarvonshire: Cwm Idwal, below Twll Du, 23/6358, 475 m, on large boulders, 1994, Fryday 5322 (E).England: V.C. 62, N. E. Yorkshire: Bransdale, 1988, D.H. Smith (hb. Fryday). Scotland: V.C. 88, Mid Perth-shire: Killin, Sron a’ Chlachain, 27/5633, 350 m, acidicschistose boulder, 1990, Fryday 1446, 1447; Glen Ogle,Glenogle Cottages, 27/5528, 350 m, exposed acid boul-der on hillside, 1991, Fryday 2051; Glen Lochay, Meallna Samhna, 27/4933, 600 m, 1991, Fryday 2345. V.C.100, Clyde Islands: Arran, Blackwaterfoot, near King’scave, 16/8831, sea level, on Old Red Sandstone boulder


near the sea, 1984, B. J. Coppins 10181 (E). V.C. 106,West Ross-shire: Kintail, Gleann Choinneachain, 18/9822, 150 m, acidic crag, 1993, Fryday 4500.—Ireland: V.C. H1, South Kerry: Dingle Peninsula,Connor’s Pass, Lough Doon, 01/5006, 500 m, sand-stone boulder, 1994, Fryday (5192) & O. L. Gilbert;Mt Brandon, Lough Avoonane, 01/46 08, sandstonecrags and boulders above and south of tarn, 1994,Fryday (5252) & O. L. Gilbert.

Porpidia contraponenda (Arnold)Knoph & Hertel

In Hertel & Knoph, Mitt. Bot. Staatssamml. München20: 477 (1984).—Lecidea contraponenda Arnold, Verh.K. K. Zool.-Bot. Ges. Wien 36: 79 (1886); type: Austria,Tirol, 1884, Arnold (Arnold, Lich exs. 1055;M—lectotype, H—isolectotype!).

Porpidia diversa (Lowe) Gowan syn. nov., Bryologist92: 42 (1989).—Lecidea diversa Lowe, Lloydia 2: 256(1939); type: USA, New York, Mount Marcy (nearLake Placid), 4900 ft, on rock face in gully, 17 Aug1934, Lowe 4283 (MICH—holotype!).

Porpidia contraponenda is usually character-ized by having a thallus containing themethyl 2#-O-methylmicrophyllinate chem-osyndrome. However, several other speciesin the genus produce a wide variety of sec-ondary metabolites (Gowan 1989a, b) andso it is likely that P. contraponenda will alsohave a variable chemistry, and that P. con-traponenda will not be the only species(excluding the North American P. diversa,which is here considered to be a synonym ofP. contraponenda) to contain this chemosyn-drome. Indeed, a specimen from MeallDhun Croisg, Mid Perthshire (Fryday3374) contains methyl 2#-O-methylmicro-phyllinate but is morphologically identical toP. rugosa (syn. P. glaucophaea—see below)having a thick glaucous thallus, and sessilepruinose apothecia with an ‘albocaerulescens-type’ exciple. Two further specimens (Cop-pins 16276, Fryday 2034) contain methyl2#-O-methylmicrophyllinate, have a thick,white, sorediate thallus, and are morphologi-cally most similar to P. pachythallina Fryday(see below).

Gowan & Ahti (1993) correctly consid-ered P. contraponenda to be closely related toP. cinereoatra, and this close relationship issupported by molecular data (Buschbom &

Mueller 2004), which shows P. contrapo-nenda as the sister species to a clade contain-ing P. cinereoatra, P. lowiana, and P. diversa.Both species have a heavily pigmentedexciple and are separated only by secondarymetabolite chemistry (methyl 2#-O-methyl-microphyllinate in P. contraponenda, conflu-entic acid in P. cinereoatra), and P. ciner-eoatra having innate apothecia. Methyl 2#-O-methylmicrophyllinate and confluenticacid were shown to be closely related byGowan (1989b), who stated that ‘‘the path-ways leading to the confluentic . . . andmethyl 2#-O-methylmicrophyllinate chem-osyndromes differ mainly in the length of theacetyl-polymalonyl part of the pathway, andthey vary only slightly in methylation’’ and‘‘methyl 2#-O-methylmicrophyllinate arosein an ancestor that contained confluenticacid’’. The isolectotype of P. contraponendain H has a moderately thick thallus (0·15–0·2 mm) with apothecia that are onlyslightly, but distinctly raised above the levelof the thallus. Although the lectotype ofP. cinereoatra has immersed apothecia, othercollections referred to this species have simi-larly, slightly sessile apothecia. The morpho-logical differences between P. cinereoatra andP. contraponenda are, therefore, slight andthe separation of the two species is worthy offurther investigation.

Porpidia diversa (Lowe) Gowan, describedfrom north-east North America, has an iden-tical chemistry to P. contraponenda. Gowan(1989a) separated the two species only byP. diversa having smaller apothecia, a morebluish epihymenium and outer exciple, anda disjunct distribution (in North America, P.diversa is restricted to the north-east whereasP. contraponenda has been recorded fromonly the Pacific Northwest). The differencesin pigmentation and apothecia size appear tobe subtle and are difficult to identify fromGowan’s descriptions as she describes theepihymenium of both species in terms of anolivaceous pigment, and the range of apoth-ecia sizes have considerable overlap. Inaddition, the holotype of Lecidea diversaLowe has a brown (Arnoldiana-brown) epi-hymenium, and all other specimens that Ihave seen that have been annotated as this


species by Gowan have either an oliva-ceous (Macrocarpa-green) or brown epihy-menium. The apothecia of the holotype aresmaller than is usual for P. contraponenda(c. 0·3 mm), but they have a very thickproper margin that almost completely ob-scures the disc and are clearly immature.Other collections from north-eastern NorthAmerica, identified as P. diversa by Gowan,have apothecia over 1·5 mm diam. andclosely resemble the lectotype of P. contrapo-nenda. Gowan & Ahti (1993) found thedistinction between the two species less pro-nounced in Fennoscandia and included col-lections from Finland with small apotheciaand a thin thallus in P. contraponenda onaccount of their olivaceous epihymenialpigmentation. It appears that the maindistinction made by Gowan between P. con-traponenda and P. diversa was distribution,and this is insufficient justification for recog-nizing a separate species for a crustose lichenthat is only reliably separated from a numberof other species by subtle, microscopicmorphological characters and thin-layerchromatography.

There are five Porpidia collections fromthe British Isles that contain methyl 2#-O-methylmicrophyllinate and also producesoredia. As mentioned above, two of these(Coppins 16276, Fryday 2034) are probablyreferable to P. pachythallina, but the othersappear to represent a distinct entity. The twocollections from Scotland (Coppins 13792,Fryday 1373) lack apothecia but thatfrom Wales (Chambers s.n.) is abundantlyfertile with sessile apothecia c. 1·0 mm diam.and a thick proper margin c. 0·1 mm wide.Ascospores are c. 20�10 �m and thehymenium 120–130 �m tall and composedof paraphyses that are richly branched nearthe apex and have a distinctly swollen (4–5 �m), pigmented hood. The exciple isdarkly pigmented with a slightly paler me-dulla and composed of radiating hyphae3–4 �m thick. These characters, especiallythe structure of the paraphyses, suggest thatthis entity does not belong in P. contrapo-nenda, but more material is required toascertain its correct taxonomic position.

Selected specimens examined. Great Britain: Wales:V.C. 46, Cardiganshire (Ceridigion): Strata Florida,22/744662, 180 m, block spoil from disused metal-mine, 1993, Fryday 4206. V.C. 49, Caernarvonshire:Clogwyn y Garnedd, 23/6154, 700 m, acidic rock,October 1996, Fryday s.n. Scotland: V.C. 88, MidPerthshire: Ben Lawers NNR, W of Creag nanFhithich, 27/6342, 950 m, low flat rock, 18 July 1989,Fryday; Killin, Sron a’ Chalchain, 27/5633, 300 m, acidschistose boulder, 1990, Fryday 1444, 1445; ibid., Alltna Ceardaich, 27/5734, 175 m, acidic boulder, 1991,Fryday 2026; ibid., Glen Lochay, Meall Dhun Croisg,27/5435, 350 m, mica-schist outcrop by stream, 1992,Fryday 3370. V.C. 97, West Inverness-shire: Ben Nevisrange, Aonach Mór, near bealach with Aonach Beag,27/1972, c. 1100 m, small stones, 1991, Fryday 2710;Creag Meagaidh, northwest of summit, 27/407871,1000 m, on small pebble above area of late snow-lie,1994, Fryday 5635. V.C. 98, Argyll Main: Glen Coe,Coire nam Beitheach, 27/1454, 850 m, acidic rock,1992, Fryday 3407. V.C. 103, Mid Ebudes: Isle ofMull, Ardmeanach, Burg, Bearraich, 17/4127, 250 m,basalt boulder, 1993, Fryday 4441. V.C. 110, OuterHebrides: North Harris, Clisham, near AbhainnMhàraig, 19/1606, 350 m, siliceous boulder, 1991,Fryday 2593.—Ireland: V.C. H1, South Kerry:Mt Brandon, summit heath, 01/4711, c. 900m, smallpebbles, 1994, Fryday (5288) & O. L. Gilbert.

Porpidia diversa. USA: New York: Mount Marcy(near Lake Placid), 5300 ft, on sheltered rock, 1933, J.L. Lowe 3024 (MICH); along Marcy brook belowIndian Falls, 2600 ft, on rocks, 1936, J. L. Lowe 6289(MICH); ibid., 2700 ft, on rocks, 1936, J. L. Lowe 6360(MICH).

Sorediate specimens. Great Britain: Wales: V.C. 46,Cardiganshire (Ceridigion): Ystumtuen mine, 22/734788, 290 m, on vertical south-facing open-cut, 11June 1992, S. P. Chambers (hb. Fryday). Scotland: V.C.88, Mid Perthshire: Killin, Allt na Ceardaich, 27/5734,225 m, top of acidic boulder, 1991, Fryday 2034. V.C.97, West Inverness-shire: Ben Nevis range, AonachMór, summit plateau, 27/1972(–3), 1150–1221(c. 1200) m, small stones, 1990, B. J. Coppins (13792),A. M. Fryday & O. L. Gilbert (E); Ben Nevis, summitplateau, 27/1671, 1340 m, south-facing, exposed acidrocks, 1990, Fryday 1373. V.C. 101, Kintyre: 5 kmSW of Skipness, Claonaig Wood SSSI (Coille RubhaDhuibh) 16/8655, 0–60 m, on sea-shore rocks interrestrial zone, 1994, B. J. Coppins (16276) & A. M.O’Dare (E).

Porpidia crustulata (Ach.) Hertel &Knoph

In Hertel, Beih. Nova Hedwigia 79: 435 (1984).—Lecidea parasema � L. crustulata Ach., Lichenogr. Univ.:176 (1810).—Lecidea crustulata (Ach.) Spreng., Syst.Veget., edit. 16, 4: 258 (1827); type: Switzerland,Schleicher 690 (H-ACH—lectotype!).


(Figs 2A, B & E)

As suggested by Gowan & Ahti (1993),Porpidia crustulata appears to be the non-sorediate counterpart of P. soredizodes (Lamyex Nyl.) J. R. Laundon. Molecular data

(Buschbom & Mueller 2004) indicate avery close relationship with P. macrocarpa,but the specimen used for this analysiswas collected from northern Sweden(Abisko), and is unlikely to be P. crustulatas. str.

F. 2. Porpidia crustulata and P. macrocarpa. A, lectotype of Lecidea parasema var. crustulata (left) and holotype ofPatellaria macrocarpa (right); B, thallus and apothecia of lectotype of Lecidea parasema var. crustulata; C, matureapothecium of holotype of Patellaria macrocarpa; D, immature apothecium of holotype of Patellaria macrocarpa; E,cross-section of excipulum of lectotype of Lecidea parasema var. crustulata; F, cross-section of excipulum of holotype

of Patellaria macrocarpa. Scales: A, B & C=1 mm; D=0·5 mm; E & F=50 �m.


The lectotype of Lecidea parasema � L.crustulata Ach., like many other collectionsin the P. macrocarpa group, has only brownpigments in the epihymenium, whereasothers also contain Macrocarpa-green. Asin Rhizocarpon infernulum (Nyl.) Lynge(Fryday 2002), this is most probably due tothe degree of light to which the specimen hasbeen exposed, and is of no taxonomic sig-nificance. The exciple of the lectotype ismoderately pigmented, without a darkercortex, in fact the cortical cells are unpig-mented. It appears that only the blue-greenpigment (Macrocarpa-green), when present,occurs in the exciple cortex giving it a darkblue-black colour, and in specimens lackingthis pigment, the exciple cortex is no darkerthan the rest of the exciple.

Porpidia crustulata is usually characterizedby a combination of small apothecia, wideexcipular hyphae, small ascospores, and lowhymenium. However, these characters areall related (Table 2), and the species is bestseparated from P. macrocarpa, as suggestedby Schwab (1986), by having smaller apoth-ecia with a less massive proper margin (Fig.2). The separation of P. crustulata fromP. macrocarpa is discussed in detail under thelatter species.

Specimens examined. Great Britain: date and localityunknown J. Whinham (hb, Fryday).—Canada: BritishColumbia: Revelstoke National Park, West WolseyCreek Valley, east side of park, 51(08#N, 117(57#W,3100 ft, on boulder in forest shadow, 1970, G. F. Otto3136 (CANL).—USA: Michigan: Iron Co., hardwoodsnear Teepee Lake, T.46.N., R.37.W., sec 13, 18 ix1964, R. C. Harris s.n. (MSC); Alger Co., old burnedarea east of Kingston lake, T.48N., R.15.W., sec 5, 21ix 1964, R. C. Harris s.n. (MSC). Wisconsin: Price Co.,on pebbles on earth bank one mile east of Fifield, 1958,J. W. Thomson & M. E. Hale 5132 (MSC); BayfieldCo., Squaw Point, on lake Superior at Cornucopia,

Betula papyrifera–Acer saccharum woods, 46(45#N,90(00#W, on rocky sandstone ledge at lake edge, 1965,I. M. Brodo 5805 (MSC); Ashland Co., Apostle IslandNational Lakeshore, Bear Island, rocky point on NEshore and in woods with yew, balsam fir and birch, Sec.28, T53N, R3W, 47(44#47$W, 615 ft, 2001, C. M.Wetmore 87124 (MSC).

Porpidia diversa (Lowe) Gowan – seePorpidia contraponenda

Porpidia flavocruenta Fryday &Buschbom sp. nov.

Porpidiae flavicundae similis sed excipulo cellulo; cellulis6·0–8·5 �m latis, thallo sine substantiis lichenis.

Typus: Caledonia: V.C. 88, Mid Perthshire, BenLawers NNR, Coire Riadhailt, 27/5738, 750 m, onacidic mica-schist boulder, 11 June 1992, A. M. Fryday3132 (E—holotypus).

Porpidia macrocarpa var. hercynica nomen ad interim,Schwab, Mitt. Bot. Staatssamml. München 22: 422–423(1986).

(Figs 3A, 5A)

Thallus epilithic, thin to moderately thick,0·1–0·2 mm, yellow-orange, occasionallypale yellow-grey, cracked-areolate, surfaceuneven with low warts from which theapothecia arise; black prothallus visible atedges where adjoining other lichens. Photo-biont chlorococcoid, cells 8–10(–15) �mdiam.

Apothecia black, lecideine, large (0·8–)1·2–1·5(–2·0) mm diam., sessile with a con-stricted base, orbicular, becoming flexuosewhen mature; disc usually flat, sometimesbecoming convex in mature apothecia, occa-sionally umbonate, often grey or orange pru-inose; margin raised and persistent, 0·1 mmwide. Hymenium hyaline, I+ blue, 135–150 �m tall; epihymenium pale olivaceous

T 2. Internal characteristics of two apothecia of the lectotype of Porpidia crustulata (Lecidea parasema var.crustulata)

Diameter of Apothecia (mm) 0·3 0·6Height of hymenium (�) c. 70–80 c. 80–100Length of ascospores (�m) 14–16 15–17Excipulum cortex brown dark brown

interior �hyaline mid-brownWidth of excipular cells (�m) c. 8·0 4·0–5·0


brown (K�, N+ red; Macrocarpa-green);subhymenium hyaline, c. 50 �m. Paraphysesnumerous, branched and anastomosing,very thin, 1–1·5 �m wide, with scarcelyswollen apices. Asci cylindrical 70–80�15–17 �m, Porpidia-type. Ascospores hyaline,halonate, non-septate, ellipsoid 15–19�8–

10 �m. Hypothecium c. 100 �m high, darkbrown (K�, N�; Arnoldiana-brown).Excipulum cupular, composed of radiating,cellular hyphae, inner cells orange-brown(K+ crimson or K�, N�; �unknownpigment), c. 6·0–8·5 �m wide, outer rim(17–25 �m wide) blue-black (K� crimson,

F. 3. Thalli and apothecia. A, P. flavocruenta (Fryday 3132—holotype); B, P. islandica (Fryday 4445); C, P.striata (Fryday 2101—holotype); D, P. nadvornikiana (Fryday 1100); E, P. pachythallina (Fryday 3108—holotype);

F, P. superba f. sorediata (Fryday 3415—holotype). Scales: A & F=2 mm; B, D, & E=1 mm; C=0·5 mm.


N+ red; Macrocarpa-green, unidentifiedpigment �), composed of globose cellsc. 12·5 �m diam.

Conidiomata frequent; pycnidia, 0·1–0·15 �m diam., black, innate to sessile, withan orange pseudothalline margin, surfacegnarled when old. Conidia bacilliform,(10–)12–14�0·8 �m.

Chemistry. K�, C�, KC�, Pd�. Nosubstances detected by TLC.

Previously (Fryday 1997a), I referred toPorpidia collections from the British Isleswith an orange, non-sorediate thallus as P.aff. flavicunda, suggesting that they were notconspecific with P. flavicunda (Ach.) Gowan(syn. P. flavocoerulescens (Hornem.) Hertel &A. J. Schwab—see below under P. flavi-cunda). Molecular data (Buschbom &Mueller 2004) supports this opinion andindicates that P. flavocruenta (as P. nigro-cruenta and Porpidia sp. 2) is a memberof the P. macrocarpa group, a position thatis in agreement with its morphologicalcharacters.

This taxon was recognized by Schwab(1986), who referred several of his collec-tions from the Harz Mountains to it, as P.macrocarpa var. hercynica nomen ad interim.However, although he mentions the K+crimson reaction of the exciple, he consid-ered the diagnostic characters to be theorange thallus that consistently lacked sticticacid, and a brown (not greenish) epihy-menium. As he attributed the former to theaccumulation of iron granules in the cortex,and correctly considered that the lattercharacter was not a consistent differencefrom P. macrocarpa, he concluded that therewere insufficient differences for a formaldescription, even at the level of variety, andthat corroborating ecological evidence wasrequired. However, the species often occurson rocks with no apparent iron content, andin mosaics with other species that have agrey thallus. The colour is also much moreyellowish than the rusty-red colouration pro-duced by iron accumulation. The lack ofstictic acid also appears to be a consistentcharacter, and the K+ crimson reaction of

the exciple is further evidence that a distinctentity is involved. Porpidia flavocruenta alsodiffers from P. macrocarpa in that the apoth-ecia are usually pruinose, and that themedulla of the exciple is much darker pig-mented and composed of narrower hyphae.Because of these multiple differences fromP. macrocarpa, P. flavocruenta is here recog-nized at the rank of species, although theentities in this group appear very closelyrelated and it is possible that recognitionat an infraspecific rank may be moreappropriate.

The K+ crimson pigment was dismissedby Gowan (1989a) as taxonomically unim-portant because she had observed it in sev-eral North American species. However,although the exciple and/or hypothecium ofother members of the genus occasionallyexhibit a K+ reddish coloration, I haveotherwise observed the K+ crimson solutiononly in the P. macrocarpa f. nigrocruenta(Anzi) Fryday (see below). As this pigmentwas absent from only three of the over 30specimens of P. flavocruenta studied, Iconsider it to be a taxonomically significantcharacter.

Porpidia flavocruenta differs from P. flavi-cunda, primarily, in having a thallus lackinglichen substances by TLC, and an exciplecomposed of thick hyphae, 6–8 �m wide(2–4 �m in P. flavicunda), and which usuallycontains an unidentified, K+ crimson pig-ment. It also has a lower hymenium withmore branched and anastomosing paraphy-ses. Porpidia flavocruenta is very difficult toseparate from P. flavicunda on gross mor-phology alone, and as the two species aresympatric—although they possibly occupydifferent ecological niches—all field recordsof P. flavicunda should be treated withcaution.

Porpidia flavocruenta is widespread inEurope. It is known from a number of sitesthroughout Scotland and Wales, where itoccurs on siliceous rocks, often in shadedoverhangs or other damp habitats, and isapparently not rare at Abisko (Sweden) andthe Austrian Alps (J. Buschbom pers.comm.). It is also known from Norway(P. M. Jørgensen pers. comm.), Iceland and


North America. There is little doubt thatinvestigation of further collections referredto P. flavicunda will reveal many morespecimens of this species.

Additional specimens examined. Great Britain: Wales:V.C. 46, Cardiganshire (Ceridigion): Plynlimon Mine,22/794857, 550 m, south-facing rock-face, 1994,Fryday (5004), S. P. Chambers & R. Woods. V.C. 47,Montgomeryshire: Dylife, 22/862934, 375 m, blockspoil on disused lead mine, 1994, Fryday (5071) & S.P. Chambers. Scotland: V.C. 72, Dumfries-shire: Mof-fat, [36/00], v 1882, Rev. G. M. Conachie (E). V.C. 76,Renfrewshire: Whitelee Forest nr. Eaglesham and Car-rot Farm, 26/583482, 260 m, on trachy-basalt boulder,open boulder scree, x 2003, J. R. Douglass (E). V.C. 88,Mid Perthshire: Killin, Sron a’ Clachain, 27/5633,400 m, side of acidic boulder, 1991, Fryday 2009,2010; ibid., Glen Lochay, Meall Ghaordaidh, Allt anFhaing, 27/5239, 650 m, low, acidic rock, 1991, Fryday2132; ibid., west side of Coire Loaghain, 27/5140,750 m, shaded side of acidic rock, 1991, Fryday 2293;ibid., Beinn Heasgarnich, Creag nam Bodach, 27/4438,550 m, horizontal acidic boulder, 1991, Fryday 2148;ibid., Creag na h-Achlarich, 27/4238, 750 m, under-hang on acid rock, 1991, Fryday 2160; ibid., Kenknock,27/4735, 325 m, underside of acidic mica-schist boul-der, 1991, Fryday 2298; Ben Lawers NNR, Ben Ghlas,north coire, 27/624407, 850 m, 1991, Fryday 2955;Coire Riadhailt, 27/5738, 750 m, on acidic mica-schistboulder, 1992, Fryday 3132 (topotype). [V.C. 89, EastPerthshire:] Ben Beck [?Ben Vrackie], iii 1845, J. ForbesYoung (BM). V.C. 90, Angus: Caenlochen Glen (Wside), Craigie Doubs, 37/1776, 800–850 m, east-facingcliffs, 1989, B. J. Coppins (13403) & O. L. Gilbert (E).V.C. 92, South Aberdeenshire: Ballochbuie Forest,above Bridge of Dee, 37/1890, 335–460 m, on wallbelow north-east-facing cliff, 1984, B. J. Coppins(10638) et al. (E); Lion’s Face, 2 miles E of Braemar,37/167917, 420 m, on acid rock of cliff, E facing, 1998,B. J. Coppins (17958) & A. M. Coppins (E); CreagClunie and Lion’s face SSSI, 2 miles E of Braemar,boulder field below Charter’s Chest, 37/178914,c. 330 m, on siliceous boulders, 1999, B. J. Coppins(18264) & A. M. Coppins (E). V.C. 97, WestInverness-shire: Ben Nevis [27/17], 15 viii 1836, Lind-say (E). V.C. 98, Argyll Main: Ben Cruachan, 27/0729,700 m, 1994, Fryday 5578. V.C. 103, Mid Ebudes: Isleof Mull, E coire of Ben More, [17/5333], 700 m, onscree, viii 1966, U. Duncan (E). V.C. 104, NorthEbudes: Isle of Skye, [Trotternish], Quiraing, [18/4569,] viii 1836, Lindsay (E). V.C. 105, West Ross-shire: Loch Maree, c. 3 km SE of Letterewe House,gully of Allt Dearg, 18/979698, 245–305 m, 1986, B. J.Coppins (11887) & R. G. Woods (E). V.C. 108, WestSutherland: Ben Hope, west-facing crags, 29/4749,380–550 m, epidiorite band, iron-rich rocks below,1984, B. J. Coppins (10340) & O. L. Gilbert (E); ibid.,on iron-rich rocks, below epidiorite band, 1984, B. J.Coppins (10341) & O. L. Gilbert (E: exciple K�).—Ireland: V.C. H1, South Kerry: Dingle Peninsula,

Connor’s Pass, Lough Doon, 01/5006, 500 m,sandstone boulders above the lough, 1994, Fryday(5209) & O. L. Gilbert.—Iceland: West Iceland:Þorskafjarðarheiði, Loc: 3642Inv, Hnit: 65,67139(No22,02985(Ve, 478 m, á basalti á stógryttum fjallamel,2002, H. Kristinsson 48203 (L–29377) (MSC, F). EastIceland: Kollavík þistilfirði, Loc: 3435INo, N-þing.,Hnit: 66,28352(No 15,84925(Ve, 150–160 m, á ba-salti á stógryttum fjallamel 2002, H. Kristinsson 48204(L–29378) (MSC, F).—Sweden: Torne Lappmark:Norrbotten, Kiruna, Karkevagge, valley W of Abisko,NE-talus slope down from Vassejietanja, across fromthe plateau between first and second moraine blockinglake Rissajarvi, stabilized talus slope, boulder alongpath, 2001, J. Buschbom 2001–41 (F).—Austria:Steiermark: Stubalpe W of Graz, Summit of Speikkogel,boulder field W of top, 47(3#N 14(1#E, 700 m, lowboulder fields and single boulders and schist platessticking out of the ground in heath vegetation, 2001,J. Buschbom 14.9.2001–9 (F); Salzburg, Hohe Tauern,Venediger Group, Hintersee at the Felber Tauern pass;along hiking path up to the St. Poltner Hut, 47(12#N12(29#E, 1700 m, at forest limit, low boulder in alpinemeadow, 2001, J. Buschbom 16.9.2001–10 (F).—USA:Alaska: North Slope, ridge ENE of Okpiiak lake,144(04#W, 69(24#N, 1600 m, barrens on windsweptcliff, 1957, J. E. Cantlon & W. T. Gillis 57–1859(MSC).

Porpidia herteliana Gowan—see P. cinereo-atra

Porpidia islandica Fryday, Knoph &Hertel sp. nov.

Porpidiae superbae similis sed thallo cinereo, rimoso-areolato, apotheciis nigris, paraphysibus apice benedelimitato brunneo, et ascosporis parvioribus 16·5–18·5�8–9·5 �m.

Typus: Islandia, Auster-Barðastrandarsýsla, Olafs-dalur, 65(24#25$–65(30#N, 21(44#26$W, 20–80 m,vor allem talgrund-nahe NE-Hänge oberhalb desBaches Lambadalsá. Schutthänge und schuttbedeckteTerrassen. 20 July 1979, H. Hertel 23 061 (M—holotypus), 23 053 (M—topotypus).

(Figs 3B, 4)

Thallus epilithic, thin, c. 0·1 mm thick,cracked-rimose to slightly areolate; areolae0·2–0·3 mm across, flat, pale grey with blackprothallus sometimes visible at edges ofareolae and at thallus margin; corticalcells blue-grey (Macrocarpa-green), c. 3 �mdiam. Photobiont chlorococcoid, cells 8–10(–15) �m diam.

Apothecia black, lecideine, epruinose,(0·7–)0·8–1·0(–1·2) mm diam., sessile,


somewhat constricted below and withslightly concave disc; proper margin smooth,persistent, slightly raised, 0·1 mm wide.Hymenium hyaline, I+ blue, 110–140 �mtall; epihymenium pale brown (Arnoldiana-brown), 30 �m tall; subhymenium hyaline,25–30 �m tall. Paraphyses numerous, verythin with distinct, brown-pigmented caps (to3·5 �m), sparingly branched and anasto-mosing except in upper 20 �m where theyare regularly branched. Asci cylindrical75–80�17–20 �m, Porpidia-type. Ascosporeshyaline, halonate, non-septate, ellipsoid16·5–18·5�8–9·5 �m. Hypothecium darkbrown, 180–200 �m tall (including excipu-lum). Excipulum heavily and uniformly pig-mented, composed of radiating hyphae, c. 2–3 �m wide near hypothecium becomingwider (to 5–7 �m) near outer edge, lackingwell-defined cortical cells (in thin section,after pre-treatment with C).

Conidiomata frequent; pycnidia, 0·05–0·2 �m diam. black, innate with a whitepseudothalline margin when young, becom-ing sessile with a gnarled surface when old.Conidia bacilliform 5–6�0·8 �m.

Chemistry. K�, C�, KC�, Pd�. Nosubstances detected by TLC. Medulla I�.

Porpidia islandica most closely resemblesP. macrocarpa in gross morphology, althoughit can usually be distinguished from thatspecies by its epilithic, grey thallus (P. mac-rocarpa usually has an endolithic thallus)and, although the two species can occurtogether, P. islandica usually occurs onsomewhat basic rocks (basalt, schist). Theapothecial anatomy of P. islandica is closer toP. cinereoatra, with which it shares the heav-ily pigmented exciple. However, it differsfrom P. macrocarpa, P. cinereoatra, and most

F. 4. Paraphyses of Porpidia islandica (Fryday 4445) in 10% KOH. Scale=10 �m.


other species of the genus, in having para-physes with distinctly swollen pigmentedcaps (Fig. 4), and occurring on basicrocks.

Porpidia islandica is apparently restrictedto oceanic areas of Northern Europe,having been reported only from Iceland andScotland. One of the Scottish localities (Isleof Mull) is one of only two British localitiesfor Koenigia islandica L. (Iceland Purslane).Lichen species associated with the Icelandicspecimens include Acarospora sp., Lecideacommaculans, and Porpidia macrocarpa,whereas Porpidia superba was associated withthe collection from the Central Highlands ofScotland (Meall na Samhna).

Additional specimens examined. Iceland: Rangárval-lasýsla: c. 7 km NW des Berges Nyðri Háganga,64(37#35$N, 18(20#W, 730–750 m, Blockschuttfeldermit niedrigen, mürben Felsblöcken, 1979, H. Hertel 21888 (M); Árnessýsla: Am Wasserfall des Baches Groen-dalsá, c. 3 km NNW-lich Hveragerði, 64(01#20$N,21(12#W, 60–80 m, steile, z.T. wasserrüberrieselteBasalt-Felsflächen, Block im Bach; knapp über Wasse-roberfläche, 1979, H. Hertel 23 183.—Great Britain:Scotland: V.C. 88, Mid Perthshire: Meall na Samhna,Glen Lochay, Killin, 27/4833, 700 m, mica-schistcrags, 1991, Fryday 2352 (E); V.C. 103, Mid Ebudes:Isle of Mull, Ardmeanach, Bearraich, 17/4127, 400 m,basaltic rock in summit heath, 1993, Fryday 4445(E, MSC).

Porpidia lowiana Gowan

Bryologist 92: 49 (1989); type: Canada, NorthwestTerritories, unnamed tributary of the Arctic RedRiver, 120 miles WNW of Norman Wells, Bird 19965(WIS—holotype!).

The holotype of P. lowiana (WIS) differssignificantly from specimens referred to P.cinereoatra in having a much thinner thallus,with sessile, flat apothecia that also have apersistent, raised, thick (c. 0·1 mm) propermargin. In P. cinereoatra the apothecia aretypically innate and convex with a scarcelyraised, thin (c. 0·05 mm) proper margin thatoften becomes excluded in mature apoth-ecia. The internal structure of the excipulumalso appears to differ, being more heavilypigmented in P. lowiana. Porpidia lowianaapparently also has a more arctic distri-bution than P. cinereoatra, and this is sup-ported by the single collection confirmed

from the British Isles, which is from highaltitude in the Scottish Highlands (see be-low). However, as acknowledged by Gowan& Ahti (1993), where the distributions of thetwo species overlap, intermediates occurthat can be difficult to place, and severalcollections from the British Isles fall into thiscategory. Molecular data (Buschbom &Mueller 2004) indicates that P. lowiana isvery closely related to P. cinereoatra, but atthis stage it is maintained as a distinctspecies.

Additional specimens examined. Great Britain:Scotland: V.C. 97, West Inverness-shire: Fort William,Aonach Mór, north of bealach, 27/1972, 1100 m,schistose rock near cornice snow-bed, 1990, Fryday1330E.—Canada: Newfoundland: Trinity Bay, Heart’sEase, 22 iv 1895, A. C. Waghorne (MIN). NewBrunswick: Northumberland Co., Mt. Fronsac,47(24#30$N 66(21#10$W, at summit on SW boulderytalus slope, on talus, 1989. E. Haber (4210) & S.Priestman (CANL). Nova Scotia: Cape Breton Co.,Cape Breton Island, vicinity of Sydney, c. 85 m, on ablock of sandstone in heathy pasture with shelteredbirch trees, 1952, I. M. Lamb 7013 (CANL).—USA:New York: Adirondack Region, Chapel Pond (nearSt Huberts) 1600 ft, on rock, 1933, J. L. Lowe 3738(CANL); ibid., Warrensberg, on rock on cliff, 1936,J. L. Lowe 5934 (WIS), 5962 (CANL).

Porpidia macrocarpa (DC.) Hertel &A. J. Schwab

In Hertel, Beih. Nova Hedwigia 79: 437 (1984).—Patellaria macrocarpa DC. in Lam. & DC., Fl. Franç.Ed. 3, 2: 347 (1805); type: France (G—holotype!).

(Figs 2A, C, D & F)

The Porpidia macrocarpa aggr. is a groupof very closely related entities; the separationof P. crustulata and P. macrocarpa, in particu-lar, having long been the cause of confusion.The situation was summed up admirably byHarris (1977) who said of these two species‘‘In Michigan I have found this group sovariable and overlapping that I feel it is notworth my time or anyone’s time to try toseparate them’’. Vainio (1934) separated thetwo species by P. crustulata having a lowerhymenium; 50–70 �m against 80–125 �mfor P. macrocarpa (as P. steriza), whereasHertel (1975, 1977) preferred to sep-arate them by P. crustulata having smaller


apothecia and ascospores, and Inoue(1983) by height of hymenium and size ofascospores. However, Schwab (1986) foundall these characters to be unreliable andsuggested that the maximum diameter of theapothecia and the width of the proper mar-gin were better characters. In contrast, Ram-bold (1989) found that the two species werereadily separated in Australian material, P.crustulata having a thallus containing sticticacid, smaller apothecia and ascospores, andoccurring at lower altitudes. However, thiswas based on a total sample of only fourcollections. Gowan (1989a) attempted toresolve the problem by separating P. crustu-lata from P. macrocarpa on a number ofcharacters (e.g. width of excipular hyphae,height of hymenium, size of ascospores,distribution), and describing a third species,Porpidia thomsonii (see below), as inter-mediate between them.

Investigation of the lectotype of Lecideaparasema � L. crustulata Ach. (the basionymof P. crustulata) and the holotype of Patel-laria macrocarpa DC. (the basionym of Por-pidia macrocarpa) confirmed the observationmade in other collections referred to thesetwo species that the pigmentation of theexciple, width of excipular hyphae, size ofascospores, and height of hymenium are allrelated to the size of the apothecia (Table 2).Consequently, the separation of P. crustulatafrom P. macrocarpa proposed by Vainio,Hertel, Inoue and Gowan cannot be sup-ported. The only characters remaining aresize of apothecia, width of proper margin,and distribution; and the two type collec-tions do indeed show distinct differences inthe two morphological characters (Fig. 2).Lecidea parasema � L. crustulata has smallapothecia (<0·6 mm diam.) with a thinproper margin (<0·05 mm wide), whereasPatellaria macrocarpa has large apothecia (to2·2 mm diam.) with a thick tumid margin(0·15–0·2 mm wide). Smaller apothecia ofPatellaria macrocarpa (0·4–0·5 mm diam.)have the same thick, raised proper margin aslarger apothecia, with the consequence thatno disc is visible. This contrasts with apoth-ecia of Lecidea parasema � L. crustulata withthese dimensions, which have a thin proper

margin and a well-developed disc, 0·3–0·4 mm diam.

The identification of typical specimens ofeither species, therefore, is not difficult. Inparticular, as pointed out by Schwab (1986),P. crustulata is readily identified by the nar-row proper margin, especially in smallapothecia, and the small maximum diameterof the apothecia. However, even after P.crustulata and P. macrocarpa s. str. (largeapothecia with a thick tumid proper margin)have been removed, specimens referred to P.macrocarpa are still extremely variable. It isprobable, as suggested by Gowan (1989a),that other taxa are involved, but the charac-ters she considered diagnostic for P. thomso-nii (width of excipular hyphae and endolithicthallus) are insufficient to fully characterizethe species (see below). A study combiningmolecular, morphological, chemical and dis-tributional data is probably required to elu-cidate species concepts and boundaries inP. macrocarpa s. lat.

Two other species, P. flavocruenta and P.platycarpoides, are also closely related to P.macrocarpa, but both are characterized bydistinctive morphological characters. Por-pidia flavocruenta has an orange thallus andapothecia with a darker exciple that containsa K+ crimson pigment (also present in thehypothecium), whereas P. platycarpoides haspruinose apothecia and a relatively welldeveloped thallus that usually containsnorstictic acid. An additional entity that isseparated from P. macrocarpa by havinggenerally smaller apothecia that have a dis-tinctive, radially striate proper margin isdescribed below as P. striata, whereas P.nigrocruenta, which is separated from P. mac-rocarpa only by having an exciple with thesame K+ crimson reaction as is found inP. flavocruenta, is here recognized only asP. macrocarpa f. nigrocruenta.

Selected material examined. Great Britain: Scotland:V.C. 88, Mid Perthshire: Ben Lawers NNR, Lochan naLairige, 27/5939, 500 m, 24 viii 1989, Fryday; ibid.,Meall nan Tarmachan, bealach between on S ridge,27/5838, 900 m. low lying rocks on ground, 1990,Fryday 1457; Glen Lochay, Meall nan Subh, 27/4539,600 m, exposed rock on ground, 1991, Fryday 2100.V.C. 89, East Perthshire: Blair Atholl, Glen Tilt, 27/87,22 x 1990, K. Hill s.n. (hb. Hitch). V.C. 97, Argyll


Main: Fort William, Ben Nevis, summit plateau, 27/1671, 1340 m, top of crags affected by cornice snow-bed, 1990, Fryday 1359. V.C. 106, West Ross-shire,Kintail, Beinn Fhada, summit, 28/1019, 950 m, sili-ceous rocks, 1993, Fryday 4491. V.C. 110, OuterHebrides: West Lewis, Teinnasval, 19/0324, 350 m,siliceous boulder, 1991, Fryday 2510 & 2511.—Ireland: V.C. H1, South Kerry: Mt Brandon, summitheath, 01/4711, c. 900 m, small pebbles, 1994, Fryday(5286) & O.L. Gilbert.—USA: Michigan: Alger Co.,Lake Superior shore near Little Beaver Lake, T.48N,R.16W, Sec 7, old burned area, 25 ix 1964, R. C. Harriss.n. (MSC).

Porpidia macrocarpa f. nigrocruenta(Anzi) Fryday comb. & stat. nov.

Lecidea nigrocruenta Anzi, Comment. Soc. Crittog. Ital. 2:18 (1864).—Porpidia nigrocruenta (Anzi) Diederich &Sérus., in Diederich, Sérusiaux, Aptroot, & Rose,Dumortiera 42: 28 (1988); type: Italy (Anzi, Lich.Langob. n. 402: M—isotype, n.v.).

Porpidia macrocarpa f. nigrocruenta appar-ently differs from f. macrocarpa only in hav-ing an exciple containing a pigment thatyields a K+ crimson solution. It differs fromP. flavocruenta (which contains the same K+crimson pigment) primarily, in having agrey, �endolithic thallus. It has beentreated both as a distinct species (e.g. Inoue1983) and as a synonym of P. macrocarpa(e.g. Gowan 1989a). I consider the K+crimson reaction of the exciple to be ofminor taxonomic importance but, pendingfurther investigation of its taxonomic pos-ition, prefer to give the entity some taxo-nomic rank and so I recognize it at the levelof forma.

Porpidia macrocarpa f. nigrocruenta was in-cluded in previous checklists of the BritishIsles (Hawksworth et al. 1980—as Huilianigrocruenta (Anzi) Hertel, Purvis et al.1983—as a synonym of P. macrocarpa) butbecause no published, localized recordscould be found it was removed from themost recent checklist (Coppins 2002). It ishere confirmed as a British taxon.

Selected material examined. Great Britain: Scotland:V.C. 88, Mid Perthshire: Ben Lawers NNR, Meall nanTarmachan, bealach on the south ridge, 27/580382,900 m, low-laying rocks on the ground, 1990, Fryday1455; ibid., Lawers Dam, 27/601391, 525 m, mica-schist rocks by entrance, 1990, Fryday 1460. V.C. 97,West Inverness-shire: Fort William, Ben Nevis, 27/

1671, 1340 m, exposed acid rocks on summit, 1990,Fryday 1374 (E).—Sweden: Värland: Karlskoga par.,Lokadalen, N of lake Limtjärnen, 59(31#N, 14(30#E,on perpendicular rock in shaded situation, 1980, L.-E.Muhr 2626 (E).—USA: South Dakota: Custer Co.:Black Hills, along Needles Highway (S.D. 87) 3 mileseast of Sylvan lake (5·5 miles north-east of Custer), Sec.33, T. 2S., R, 5E, 5900 ft, in deep moist valley, 1960,C. M. Wetmore 7311 (MSC). Lawrence Co.: BlackHills, along Bear Butte Creek, 1·1 miles south of US385 (6 miles south-east of Lead), Sec. 17, T. 4N., R,4E, 5100 ft., steep north-facing slope above creek,1960, C. M. Wetmore 8666 (MSC); near Bridalveil Fallsin Spearfish Canyon (5 miles south of Spearfish), Sec.4, T. 5N., R, 2E, 4300 ft, in deeply shaded east-westgulch, 1960, C. M. Wetmore 9420 (MSC).—Chile:Prov. Magellanes: Straits of Magellan, W side of B.Borja, 53(32#S, 72(30#W, moorland on ridge, 1976,H. Imshaug (45206) & K. Ohlsson (MSC).

Porpidia striata Fryday sp. nov.

Porpidiae macrocarpae similis sed margine apothecii ra-diale rimuloso (subtiliter striato), excipulo in sectionetenui cum cortice carbonaceo et medulla dilutebrunnea. A Porpidia tahawasiana epihymenio olivaceodiffert.

Typus: Scotland, Caledonia, V.C. 88, MidPerthshire, Meall nan Subh, 27/4539, 770 m, onschistose stone imbedded in montane heath, 14 March1991, A. M. Fryday 2101 (E—holotypus).

(Figs 3C, 5B)

Thallus endolithic to scarcely apparent; ifvisible then composed of thin, flat, pale greyareoles, occasionally better developed withwhitish areoles when in less exposed situa-tions. Photobiont chlorococcoid, cells (3·5)4–5�5–6(–7) �m diam.

Apothecia black, lecideine, epruinose,(0·3–)0·5–1·0(–1·2) mm diam., pore-likewhen young, expanding when mature;proper margin persistent, thick (c. 0·1 mm)and raised, radially striate, especially inyoung apothecia, becoming smootherwhen mature. Hymenium hyaline, I+ blue,80–100 �m tall; epihymenium brown-olivaceous (Macrocarpa-green); subhy-menium hyaline, 20–25 �m tall. Paraphysesnumerous, very thin with swollen pigmentedcap (2·5–3·0 �m wide), branched andanastomosing, lax in K. Asci cylindrical60–70�20–25 �m, Porpidia-type. Ascosporeshyaline, halonate, non-septate, ellipsoid16–19�8–9 �m. Hypothecium dark brown,


180–200 �m tall (including excipulum).Excipulum of radiating hyphae 4·0–5·0(–8·0) �m wide, outer 10–15 �m carbona-ceous, cracked; inner cells pale brown toalmost hyaline in thin section.

Conidiomata frequent when thallus appar-ent; pycnidia, 0·05–0·2 �m diam. black withraised, white pseudothalline margin whenyoung, becoming sessile with a gnarled

surface when old. Conidia bacilliform6–8�0·8 �m.

Chemistry: no substances detected byTLC.

Porpidia striata closely resembles P. mac-rocarpa; both taxa having sessile apotheciawith a thick, tumid proper margin. Internally

F. 5. Distribution of Porpidia species in Great Britain and Ireland. A, P. flavocruenta; B, P. striata; C, P.pachythallina; D, P. superba f. sorediata.


the exciple of both taxa consists of a pig-mented outer rim with a pale brown toalmost hyaline interior, and the width of theexcipular cells of both taxa range from4–8 �m and appears to be correlated withthe size (?age) of the apothecium; smaller(?younger) apothecia having much widercells (c. 8 �m) than larger (?older) ones (4–5 �m). However, P. striata is distinguishedfrom P. macrocarpa by its generally smallerapothecia that have a distinctive, radiallystriate proper margin with a carbonaceouscortex (visible in section). The epihy-menium of P. macrocarpa also often containsonly brown pigments, with the olivaceous/blue-black pigmentation (if present) beingconfined to the cortex of the excipulum andthe adjacent epihymenium.

Porpidia striata bears a superficial resem-blance to the eastern North Americanspecies P. tahawasiana Gowan, which alsohas an endolithic thallus and apothecia witha radially striate margin. However thatspecies has only brown pigments in theapothecium (epihymenium and exciple) andthe paraphyses are very different, being moreconglutinate and less distinctly capitate. Theexciple of P. tahawasiana is also more uni-formly carbonaceous, lacking the paler innerzone characteristic of the P. macrocarpagroup. Also, in spite of the dimensions givenby Gowan, P. tahawasiana appears to havegenerally smaller apothecia than P striata. Ofthe 16 specimens (including the holotype) inMICH annotated by Gowan, apothecia aregenerally in the range 0·4–0·6 mm diam.,only rarely reaching 0·8–1·0 mm diam.

Porpidia striata is readily separated from allother European taxa of the genus by thepersistent, tumid, radially striate margin ofthe apothecia, which makes it readily iden-tifiable in the field. It is a frequent species ofsiliceous rocks and pebbles in the ScottishHighlands and North Wales, being mostfrequent on pebbles embedded in exposed,wind-swept heaths, where it is often a domi-nant species. It almost certainly occurs inScandinavia. The striate margin of P. striatais a consequence of the carbonaceous excipleof the species, and it is probable that this isan adaptation to, or a consequence of, the

extreme environmental conditions in whichthe species most frequently occurs. How-ever, even when the taxon occurs in moresheltered situations, the striate margin is stilla prominent feature. Apothecia of otherspecies of Porpidia (e.g. P. contraponenda, P.thomsonii), and other genera also occasion-ally have a striate margin when they occur inexposed situations, but it is never as pro-nounced, or as consistently produced, as inP. striata.

Associated species are few, the lichen usu-ally growing on otherwise uncolonized sur-faces, but include Protothelenella corrosa,Porpidia contraponenda, P. tuberculosa andRhizocarpon reductum. Two relevés from theEastern Highlands, from which P. striata wasrecorded, are given in Table 3.

Selected additional specimens examined. GreatBritain: Wales: V.C. 42, Breconshire: LlanwrtydWells, Abergwesyn, Nant Irfon NNR, 22/842544,c. 320 m, on low rock outcrops (Silurian shale), oftenon loose pieces of rock, 2001, B. J. Coppins (20356) &A. M. Coppins (E). V.C. 47, Montgomeryshire: Dylife,22/862934, 375 m, on block spoil from disused leadmine, 1994, Fryday (5077, 5080) & S. P. Chambers.V.C. 49, Caernarvonshire: Carnedd Dafydd, FoelMeirch, 23/6563, 800 m, siliceous pebbles in montaneheath, 1994, Fryday 5341; Glyder Fach, Bwlch yDdwy-Glyder, 23/6558, 900 m, on siliceous pebbles indamp heath just below rim of cwm, 1994, Fryday 5671;Carnedd Llewelyn, Gledrffordd, 23/7065, 750 m, sili-ceous pebble in montane heath, 1996, Fryday 7129 &7130. Scotland: V.C. 86, Stirlingshire: Ben Lomond,south-east of summit, 27/368027, 950 m, quartzitepebble in exposed schistose boulder, 1994, Fryday5662. V.C. 88, Mid Perthshire: Ben Lawers, N. ridge27/6341, 1100 m, schistose rock, 1989, Fryday s.n.;Ben Lawers NNR, Creag an Lochain, 27/5941, 550 m,mica-schist boulder, 1990, Fryday 1109; Meall nanTarmachan, top of S. ridge, 27/5838, 900 m, low lyingrocks on ground in bealach, 1990, Fryday 1456 (thickthallus); Killin, Allt na Ceardaich, 27/5734, 225 m,acidic boulder, 1991, Fryday 2028; Meall nan Subh,27/4539, 750 m, on schistose stone imbedded inmontane heath, 1991, Fryday 2107 (MSC—topotype);Ben Lawers NNR, Creag an Lochain, 27/5941650 m, exposed acid crags, 1991, Fryday 2086; BeinnHeasgarnich, West of Creag nam Bodach, 27/4438,650 m, small stone in wind-swept heath, 1991, Fryday2150; Meall nan Subh, 27/4539, 770 m, on schistosestone imbedded in montane heath, 1991, Fryday 2357(M—topotype); Cruach Ardrain, bealach betweenStob Glas and summit, 27/4020, 800 m, pebble inheath, 1992, Fryday 3039; Ben Lawers NNR, MeallCorranaich, summit heath, 27/615410, 1068 m, 1992,


Fryday (3099) & G. Coppins; ibid., head of CoireOdhar, 27/6240, 875 m, mica-schist pebble in wind-swept bealach, 1995, Fryday 6042. V.C. 92, SouthAberdeenshire: Allanaquoich, Braemar, 37/116911,350 m, on small stones in open heath, September 1997,J.D. Milne (hb. Fryday). V.C. 98, Argyll Main:Dalmaly, Beinn Eunaich, 27/1332, 850 m, pebble onexposed montane heath, 1991, Fryday 2246; Glen Coe,Bidean nam Bian, 27/1454, 1080 m, bealach south ofStob Coire nam Beith, pebble in wind-swept heath,1992, Fryday 3410. V.C. 110, Outer Hebrides: WestLewis, Teinnasval, 19/0324, 350 m, siliceous boulder,1991, Fryday 2501 & 2503; North Harris, Glen

Ulladale, Cragan Leathan, 19/0713, c. 200 m, Lewisiangniess outcrop, 1991, Fryday 2615.

Porpidia musiva (Körb.) Hertel & Knoph—see P. cinereoatra

Porpidia nadvornikiana (Vezda) Hertel

Beih. Nova Hedwigia 79: 437 (1984).—Haplocarponnadvornikianum Vezda, Preslia 44: 209 (1972); type:[Czech Republic] Bohemoslovacia, Sudeti orient., distr

T 3. Relevés collected from NVC H13 Calluna vulgaris–Cladonia arbuscula heath on Cairn Gorm, EasternHighlands that contain Porpidia striata. Values for each species are given in the Domin scale (except saxicolous lichens

where only presence/absence is recorded)

Grid ref. 38/0107 38/0005Alt. (m) 920 910Date recorded 16/6/94 18/6/94Vegetation cover (%) 95 90Height of vegetation (cm) 5 4Lichen cover (%) 35 20Gravel (%) 5 9Rocks (%) 0 1Slope (() 25 15Aspect (() 270 280

Vascular plantsCalluna vulgaris 9 8Empetrum nigrum 5 5Loiseleuria procumbens 2 4Vaccinium myrtillus 1 4V. vitis-idaea 1 —Carex bigelowii 1 3Deschampsia flexuosa — 1Juncus trifidus — 1Huperzia selago 1 1Diphasiastrum alpinum — 1

BryophytesBarbilophozia floerkei — 1Diplophyllum albicans — 1Gymnomitrion concinnatum — 1Polytrichum piliferum 1 1Racomitrium lanuginosum 1 1

Terricolous lichensAlectoria nigricans 2 2Arthrorhaphis grisea* — 1Baeomyces rufus 1 1Cetraria aculeata 2 3C. islandica 2 2

*Lichenicolous fungus on Baeomyces rufus.†Calluna vulgaris stems

Cladonia arbuscula 5 4C. bellidiflora — 1C. coccifera aggr. 1 2C. fimbriata 1 —C. furcata 2 3C. portentosa — 1C. rangiferina 1 —C. uncialis subsp. biuncialis 3 3C. zopfii — 1Dibaeis baeomyces — 1Flavocetraria nivalis 2 1Protomicarea limosa — 1Micarea leprosula — 1M. lignaria 1 2M. turfosa — 1M. viridiatra — 1Ochrolechia frigida 5 2O. tartarea — 1O. xanthostoma† 1 —Pycnothelia papillosa — 1Thamnolia vermicularis 1 1Trapeliopsis granulosa 1 —

Saxicolous lichensFuscidea kochiana — �Lecanora polytropa � �Lecidea lithophila — �L. swartzioidea — �Miriquidica pycnocarpa

(syn. Lecidea pycnocarpa)— �

Porpidia macrocarpa s. lat. � �P. striata � �P. tuberculosa � —Rhizocarpon geographicum — �Tremolecia atrata — �Umbilicaria proboscidea — �


S{amperk: ad saxa serpentine ‘‘Vysoký kámen’’ dicta,supra pagum Raškov, alt. 600 m.s.m, 20 ix 1970, A.Vezda s.n. (hb. A. Vezda—holotype, n.v.; exssicatiVezda Lich. sel. no. 1060—isotypes, n.v.).

(Fig. 3D)

Porpidia nadvornikiana is the only speciesof the genus that produces isidia. Indeed,apart from Koerberiella wimmeriana (Körb.)Stein, which has apothecia with a thallinemargin, it is the only isidiate species in thePorpidiaceae. It has previously been reportedonly from the Czech Republic and NWSpain (Sánchez-Biezma & López de Silanes1999), both times from serpentine rocks,and is here reported for the first time fromthe British Isles. The British collectionagrees with these previous collections in allrespects. Not only is the thallus covered withnumerous short, papillate isidia, but it alsocontains stictic acid, and occurred on aserpentine outcrop. The excipulum of theAyrshire collection has a moderately darkpigmented medulla and a darker cortex,composed of rectangular cells c. 4–5 �mwide, becoming enlarged (to 10 �m) and�globose towards the cortex, although thecortical cells are much smaller. This excipu-lum structure suggests that P. nadvornikianabelongs to the P. macrocarpa group.

Other lichens collected from the samelocality included Aspicilia caesiocinerea,Buellia aethelea, Porina linearis and Rinodinaorculariopsis.

Specimen examined. Great Britain: Scotland: V.C.75, Ayrshire: Girvan, Grey Hill, Lendalfoot Grasslands,25/1693, 290 m, exposed serpentine outcrop onsummit of hill, 1990, Fryday 1100 (E).

Porpidia ochrolemma (Vain.) Brodo &R. Sant.

In Brodo, Mycotaxon 56: 161 (1995).—Pertusaria och-rolemma Vain., Meddel. Soc. Fauna Fl. Fennica 6: 180(1881); type: Finland (TUR-V 5308—lectotype, n.v.).

Porpidia pseudomelinodes A. Schwab, Mitt. Bot.München 22: 428; type: Österreich, SchladmingerTauern, Steiermark, auf Blöcken nahe demSausenbach-Wasserfall, SW des Schwarzensees inKleinsölk, um1160 m, 10 vi 1973, J. Poelt (GZU—holotype, n.v.).

Porpidia ochrolemma has a smooth, �con-tinuous creamy yellow thallus, reminiscentof Ionaspis lacustris (With.) Lutzoni [syn.Hymenelia lacustris (With.) M. Choisy] butwith numerous grey-white soredia. It differsfrom P. melinodes in its smoother, morecreamy yellow, rimose thallus and in con-taining only stictic acid (P. melinodes alsooccasionally contains stictic acid butconfluentic acid is always present as well),although the morphological differences areprobably a consequence of the habitatof P. ochrolemma, which occurs on semi-inundated rocks. Porpidia ochrolemma (asHymenelia ochrolemma) and P. melinodes areboth illustrated in colour by Gowan & Ahti(1993).

In the British Isles P. ochrolemma is knownonly from North Wales (Fryday 1996a).Schwab (1986) described the apothecia ofthis species (as P. pseudomelinodes Schwab)that indicated that this species belonged tothe P. macrocarpa group. This is confirmedby molecular data (Buschbom & Mueller2004). Recent work (J. Buschbom pers.comm.) suggests that the primary species ofP. ochrolemma is an areolate species, similarin gross morphology to P. flavicunda, that isknown from Central and Northern Europeand North America, but not yet from theBritish Isles.

Selected material examined. British Isles: Wales: V.C.49, Caernarvonshire: Snowdon range, Cwm Uchaf,back wall of cwm, 23/6155, 750 m, on shaded�flushed siliceous rockface, 1995, Fryday 6337 (E).

Porpidia pachythallina Fryday sp. nov.

Porpidiae tuberculosae similis sed thallo albido, areolascrassas convexas composito, medulla non amyloidea,apotheciis non pruinosis, et hyphis excipuli tenuibus2.5–4 �m.

Typus: Scotland, Caledonia, V.C. 88, MidPerthshire, Ben Lawers NNR, Burn of Edramucky,27/614394, 675 m, on acidic mica-schist boulder bystream, 21 May 1992, A. M. Fryday 3108 (E—holotypus, MSC—isotypus).

(Figs 3E, 5C)

Thallus effuse, of dispersed, white, convexareoles 0·4–0·7 mm diam. on a black proth-allus. Soralia tuberculate, arising from the


areoles, blue-grey, 0·2–0·4 mm diam., be-coming confluent. Photobiont chlorococcoid,cells (3·5–)4–5�5–6(–7) �m diam.

Apothecia black, lecideine, epruinose,0·5–1·2 mm diam., often 2–5 apotheciaconfluent (then �2.0 mm diam.); propermargin thin and persistent, not or onlyslightly, raised, smooth, flexuose in conflu-ent apothecia. Hymenium hyaline, I+ blue,110–120 �m tall; epihymenium olivaceous(Macrocarpa-green); subhymenium palebrown to hyaline, c. 25 �m tall. Paraphysesslender, c. 1·5 �m wide, only slightlyexpanded at apex (to 2·5 �m), numerous,septate, branched and anastomosing. Ascicylindrical, 70–75�15–22 �m, Porpidia-type. Ascospores hyaline, halonate, non-septate, ellipsoid 17–21�6–7 �m. Hypo-thecium dark brown, 180–200 �m tall(including excipulum). Excipulum of cellularhyphae 2·5–4·0 �m wide, strongly pig-mented, brown with swollen, dark blue-black (N+ red), cells at the surface.

Conidiomata not seen.

Chemistry. Thallus C�, K� (but+numerous small ‘oil droplets’ when viewedin section), KC�, Pd�; confluentic acidchemosyndrome by TLC. Medulla I�.

The presence of the confluentic acidchemosyndrome and heavily pigmentedexciple suggests that Porpidia pachythallinabelongs to the P. cinereoatra group, in par-ticular, the sessile, non-pruinose apotheciasuggests a close relationship with P. lowiana.These two species also have a similar distri-bution in the British Isles, where they areapparently confined to high altitude in theScottish Highlands. Porpidia pachythallinadiffers from P. lowiana in reproducingmainly by soredia and having a thicker thal-lus composed of dispersed, white, convexareoles.

Porpidia pachythallina is most likely to beconfused with P. tuberculosa (Sm.) Hertel &Knoph, which is also sorediate and containsconfluentic acid. However, P. pachythallinahas a thicker, whitish thallus with a non-amyloid (I�) medulla. The apothecia ofP. pachythallina also differ from those of P.

tuberculosa in being non-pruinose and havinga well-developed exciple.

Porpidia pachythallina has a characteristicecology, usually occurring on the upper sur-faces of low, flat rocks at high altitude in theScottish Highlands where it is not rare. Twocollections from lower altitude (Coppins16276, Fryday 2034; see above under P.contaponenda) are possibly referable here,although they have a thallus containing me-thyl 2#-O-methylmicrophyllinate rather thanconfluentic acid. Associated species includeAspicilia caesiocinerea aggr., Lecanora poly-tropa, Porpidia macrocarpa aggr., Rhizocarponhochstetteri, and R. geographicum aggr.

Porpidia pachythallina has previously beenreferred to as P. cf. soredizodes (Gilbert et al.1988: 239) and P. ‘confluenta’ (Fryday1996a: 539, Fryday & Coppins 1998: 321).

Additional specimens examined. Great Britain:Scotland: V.C. 88, Mid Perthshire: Ben Lawers, 250 mSE of summit (‘the crater’), 27/636412, 1160 m, onboulder by area of late snow-lie, 1985, B. J. Coppins(10988), et al. (E); west side of Creag an Fhithich,27/6342, 900 m, top of low, flat mica-schist rock, 1989,Fryday (hb. Fryday); Ben Lawers NNR, south ridge ofMeall Corranaich, 27/6140, 950 m, low mica-schistrock, 1989, Fryday (hb. Fryday, fertile); Meall naSamhna, Lochan Coire Dhudhchlair, 27/4932, 735 m,vertical acid mica-schist rock beside lochan, 1990,Fryday 1165 (fertile); Ben Lawers NNR, Glen Roro,27/6141, 850 m, top of low mica-schist rock, 1991,Fryday 2123. V.C. 97, West Inverness-shire: Sunart,Beinn Resipol, 17/7565, 650 m, vertical shaded schis-tose rock face, 1992, Fryday 3192; Creag Meagaidh,northwest of summit, 27/417880, 950 m, on lowschistose boulder, 1994, Fryday 5615 (fertile). V.C. 98,Argyll Main: Stob Ghabhar, southeast of summit, 27/2345, c. 1050 m, top of low schistose boulder, 1992,Fryday 3045; Glen Coe, Lower Coire nam Beitheach,27/1455, 650 m, top of low boulder, 1992, Fryday3419. V.C. 103, Mid Ebudes: Isle of Mull, Ardmean-ach, Burg, 17/4226, 100 m, basalt crag, 1993, Fryday4431. V.C. 110, Outer Hebrides: North Harris, GlenUlladale, Cragan Leathan, 19/0713, c. 200 m, LewisianGniess outcrop, 1991, Fryday 2614 (fertile).

Porpidia platycarpoides (Bagl.) Hertel

In Nimis & Poelt, Studia Geobotanica 7 (Supplement 1):187 (1987).—Lecidea platycarpoides Bagl., Nuov. Giorn.Botan. Ital. 11: 99 (1879); type: Sardinia, inter Pula atSarocc, ad rupes granitoideas, Canepa (MOD—holotype and isotype, n.v.; fide Nimis & Poelt, 1987).


Although primarily a maritime species,Porpidia platycarpoides is not uncommon inmountainous areas. This species is usuallyeasily identified by: its white, epilithic thal-lus; sessile, pruinose apothecia; and the pres-ence of norstictic acid (K+ red, acicularcrystals) in the thallus and apothecium exci-ple. However, norstictic acid is occasionallypresent in only trace amounts (detectable byTLC), stictic acid being the major substancepresent, in which case sections of the thallusand the exciple give a yellow solution withK. Even in the absence of norstictic acid,P. platycarpoides is readily distinguished fromP. macrocarpa by its white epilithic thallus,usually pruinose apothecia, and lightly pig-mented exciple (in section). The white epi-lithic thallus and pruinose apothecia giveP. platycarpoides a superficial resemblance toP. albocaerulescens, but that species has �in-nate apothecia with a very different exciplestructure. Some morphs can also resembleP. superba (Körb.) Hertel & Knoph, but thatspecies occurs on basic rocks, has largerascospores, and a �uniformly orange-brown exciple.

Porpidia platycarpoides was not treated byGowan (1989a), although it appears on theNorth American checklist (Esslinger & Egan1995). I have not made an extensive search,but have seen at least one specimen fromNorth America (New York) that wasmis-identified as P. albocaerulescens.

Selected material examined. Great Britain: Wales:V.C. 48, Merioneth: Ganllwyd, 23/7223, 100 m, sili-ceous rock wall at edge of damp woodland, 1992,Fryday 3007. V.C. 49, Caernarvonshire: Cwm Idwal,north of Twll Du, 23/6358, 550 m, vertical, flushed�basic crag, 1994, Fryday 5329. England: V.C. 70,Cumberland: St Bees, 25/9511, c. 200 m, old red sand-stone on cliff top, 1991, Fryday 2144. Scotland: V.C.86, Stirlingshire: Ben Lomond, SE of summit, 27/372025, 875 m, on damp, east-facing, schistose boul-der, 1994, Fryday 5654. V.C. 88, Mid Perthshire: BenLawers NNR, Edramucky Burn, 27/614396, 700 m, Nside of very large boulder beside stream, 1992, Fryday3106. V.C. 98, Argyll Main: Lochgoilhead, Hell’s Glen,27/1905, 125 m, siliceous rock outcrop in wood, 1995,Fryday 6018, 6019. V.C. 99, Dunbartonshire: LochLomond, Torrinch, north side, 26/401893, <15 m,rocks above shore, 1984, B. J. Coppins 10975 (E). V.C.103, Mid Ebudes: Isle of Mull, Ardmeanach, Burg,17/4027, 100 m, basalt crag, 1993, Fryday 4434; ibid.,17/4028, 150 m, basalt crag, 1993, Fryday 4455.—

Ireland: V.C. H1, South Kerry: 8 miles south ofKillarney, near Upper Lake, oceanic woods, 1964, I. M.Brodo 5432 (MSC); Dingle Peninsula, Connor’s Pass,Lough Doon, 01/5006, 500 m, sandstone boulder,1994, Fryday (5210) & O. L. Gilbert.—USA: NewYork: Hamilton Co.: Adirondack Mountains, betweenLewey and Indian lakes, 6 miles south of Sabael, onshaded boulder, hemlock-beech-maple forest alongsidelake, 1961, I. M. Brodo 2853 (MSC).

Porpidia soredizoides (Lamy ex Nyl.)J. R. Laundon

Bot. J. Linn. Soc. 101: 104 (1989).—Lecidea crustulata[subsp.] *soredizoides Lamy ex Nyl., Flora 66: 534(1883); type: France (PC—holotype, n.v.; H-NYL16241—isotype, n.v.).

This is primarily a lowland species of sili-ceous rocks, with a thin thallus with numer-ous soredia. Apothecia are uncommon butindicate that P. soredizoides is a member ofthe P. macrocarpa group, most probably thesorediate counterpart of P. crustulata.

Porpidia soredizoides is superficially similarto P. tuberculosa, but contains stictic (notconfluentic) acid, and lacks an amyloidmedulla.

Selected material examined. Great Britain: Wales:V.C. 46, Cardiganshire (Ceridigion): Devil’s Bridge,Bodcoll, 23/758768, 270 m, crags above mine, 1994,Fryday (5027) & S. P. Chambers.

Porpidia superba (Körb.) Hertel &Knoph

In Hertel, Beih. Nova Hedwigia 79: 438 (1984).—Lecidea superba Körb. Sys. Lich. Germ. 248 (1855);type: Poland, Körber s.n. (M—isotype, n.v.).

Porpidia calcarea Gowan, syn. nov. Bryologist 92: 38(1989); type: USA, Michigan, Keweenaw Co., IsleRoyale National Park, Passage Island, Wetmore 47460(MIN—holotype!).

Porpidia superba is a species of upland,basic rocks that, typically, has a well-developed, white, bullate thallus, and apoth-ecia with a brown disc and constricted base.However, morphs also occur (particularly indamp situations) where the thallus is lesswell developed and the apothecia discdarker. These forms are united by thelarge ascospores, the dilute orange-brown(Superba-brown) epihymenium and exciple,and paraphyses with little apical swelling or


pigmentation. Two collections from Sval-bard (from the same locality) are on non-calcareous sandstone No habitat details aregiven, but an associated species appears tobe Ionaspis lacustris, and so they are probablyfrom a damp habitat, possibly with somebasic flushing. A sorediate morph of P.superba that typically has a thinner thallusand occurs on flushed, siliceous rocks isdescribed below as P. superba f. sorediata.

Gowan (1989a) introduced the newspecies P. calcarea for several collectionsfrom the shores of Lake Superior. Shedescribes this species as having charactersintermediate between P. superba and P. ze-oroides (Anzi) Knoph & Hertel, and beingseparated geographically from both species.According to Gowan, P. superba is knownfrom North America from only threespecimens, all from the Arctic. However, ifthe Lake Superior records are included in P.superba, the species has an almost identicaldistribution in the continent to P. speirea(Ach.) Kremp., which is also restricted tobase-rich rocks. I have seen material fromthe Lake Superior area that I would considertypical P. superba (Fryday et al. 2001), and asthe few specimens of P. calcarea available arewell within the range of variation of P.superba, P. calcarea is here included in thesynonymy of P. superba.

Selected material examined. Iceland: Suður-Múlasýsla:Felsküste des Berufjörður, c. 10 km NW vonDjupivogur, 64(43#35$N, 14(24#00$W, 0–40 m,Basalt-Felsbänke im Küstenbereich, leicht überhän-gende Felswand, über Basalt mit Andreaea rupestris,1979, H. Hertel 21514 (M).—Great Britain: Wales:V.C. 49, Caernarvonshire: Snowdonia, Crib Goch,23/6255, 825 m, basic crags, 1993, Fryday 4677.England: V.C. 69, Westmorland: Hay Stacks, Black-beck Tarn, 35/202128, 570 m, shaded wet rocks by lakemargin, 1998, O. L. Gilbert (E). Scotland: V.C. 88, MidPerthshire: Meall na Samhna, 27/4933, 825 m, basicmica-schist, 1990, Fryday 1160; Ben Lawers NNR,Creag an Lochain, 27/5941, 600 m, shaded mica-schist,1991, Fryday 2088; Beinn Heasgarnich, Creag nah-Achlarich, 27/4238, 700 m, shaded, mica-schist un-derhang, 1991, Fryday 2162. V.C. 97, West Inverness-shire: Fort William, Aonach Mór, north of bealach,27/1972, 1100 m, schistose crags near cornice snow-bed, 1990, Fryday 1329. V.C. 104, North Ebudes:Isle of Skye, Trotternish, The Storr, 18/4953,500 m, shaded basalt crags, 1990, Fryday 1286.—Svalbard: Kolfjellet [Kolfjället]: Van Mijen Bay [Van

Mijenfjorden], 19 viii 1926, Lynge (O).—USA:Michigan: Keweenaw County, Isle Royale NationalPark, N of Lake Desor at shore of Lake Superior,[48(00#N, 89(00#W, 185 m] on shore rocks, 1984, C.M. Wetmore 53099 (MIN).

Porpidia superba f. sorediata Frydayforma nov.

Porpidiae superbae f. superbae similis sed thallo tenuioreet soredia instructo.

Typus: Scotland, Caledonia, V.C. 98, Argyll Main,Glen Coe, Coire nam Beitheach, 27/1454, 1000 m,damp rock in north-facing coire, 14 August 1992, A. M.Fryday 3415 (E—holotypus).

(Figs 3F, 5D)

Thallus effuse, cracked-continuous toareolate, thin to moderately thick (0·4 mm),creamy-white. Soralia concolorous to some-what darker, arising from cracks in the thal-lus, irregular. Photobiont chlorococcoid, cells(3·5)4–5�5–6(–7) �m diam.

Apothecia often present, brown, lecideine,usually constricted at the base; disc epru-inose or slightly white pruinose, 0·8–2·0 mmdiam.; proper margin persistent, thickand tumid, darker than the disc. Anatomyidentical to P. superba f. superba.

Conidiomata frequent, pycnidia, 0·05–0·2 �m diam. brown with raised, whitepseudothalline margin when young, becom-ing sessile when old. Conidia bacilliform6–8�0·8 �m.

Chemistry. thallus C�, K+ yellow, Pd+orange; stictic acid and accessories by TLC.

As the apothecial and conidial charactersof the new taxon are identical to those of P.superba, I have no doubt as to its systematicposition. Porpidia superba f. sorediata differsfrom f. superba primarily in the production ofsoredia, although the two forms also havedifferent morphological and ecological ten-dencies. Although f. superba usually occurson shaded basic rocks, f. sorediata usuallyoccurs on vertical, flushed acidic or slightlybasic rocks (mica-schist, andesite, etc.).However, f. superba does occasionally occuron flushed rocks (e.g. Gilbert, 1998—seeabove) when it has the thin thallus typical of


f. sorediata, and, conversely, the thick bullatethallus, more typical of f. superba, may occa-sionally produce soredia (Fryday 3110).

Usually fertile, non-sorediate, lichenspecies occasionally produce isolated soredi-ate plants among a normal (i.e. fertile) popu-lation. However, the sorediate morph of P.superba occupies a different ecological nichefrom the typical form and, consequently, thetwo forms rarely occur together. It is, there-fore, appropriate to afford the sorediatemorph some taxonomic recognition and, asapothecia are often produced in addition tosoredia (although rarely abundantly), thereare no obvious anatomical differences, andthe ecological and morphological differencesare only tendencies, the rank of ‘forma’would appear to be the most appropriate.

Porpidia superba f. sorediata appears to besomewhat less frequent than the typicalform, being recorded from North Wales andthe Central Highlands of Scotland, and alsofrom Sweden (L.-E. Muhr pers. comm.),Svalbard, and northeast North America(Maine). The habitat of flushed rocks ap-pears to result in the production of a thinner,smoother thallus than in f. superba as thethallus is thickest where it is protected fromthe affects of flushing. However, othermembers of the genus also have a thinnerthallus when soredia are produced (e.g. P.melinodes/P. flavicunda).

This taxon was previously referred to as P.aff. glaucophaea by Fryday & Coppins (1998:316).

Additional specimens examined. Great Britain: Wales:V.C. 49, Caernarvonshire: Cwm Idwal, South of TwllDu, 23/6558, 600 m, vertical, flushed basic crags, 1994,Fryday 5327; Ysgolion Duon, Grib Lem, 23/6663,600 m, vertical, flushed basic crags, 1994, Fryday 5336;Beddgelert, Moel yr Ogof, 23/5547, 250 m, side of largeboulder below basic crags, 1994, Fryday 5344. England:V.C. 69, Westmorland: Moorhouse NNR, 35/7533,550 m limestone outcrop on bank of Moss Burn, 1997,D. McCutcheon s.n. (E). Scotland: V.C. 77, Lanark:Leadhills, lead mine spoil heaps and old buildings nearWilson’s Shaft, 26/885140, 450 m, on stones in minespoil, 1991, B. J. Coppins (14795) & A. M. O’Dare.V.C. 87, West Perthshire: Ochill Hills, N of Menstrie,ravine of third Ichna Burn, 26/8499, 200 m, in gully inshaded cliff with barytes vein and some Cu mineraliz-ation, 1987, B. J. Coppins 11832 (E). V.C. 88, MidPerthshire: Ben Lawers NNR, Lochan nan Cat, 27/6442, 750 m, mica-schist boulder near stream, 6 July

1989, Fryday (hb. Fryday); ibid., east side of MealCorranaich, 27/6140, 980 m, sloping mica-schist rock-face, 1992, Fryday 3110. V.C. 89, East Perthshire:Perth, Kinnoul Hill Quarry 37/1323, 120 m, on steepsloping, shaded rocks in quarry, 1986, B. J. Coppins11499 (E). V.C. 97, West Inverness-shire: Knoydart,Stob a’ Chearchail, 18/8303, 650 m, shaded garnetifer-ous schist in gulley, 1990, Fryday 1172, 1174; N side ofLoch Sunart, Resipole, ravine of Allt Mhic Chiarain,17/72(–3)64(–5), 50–150 m, on steeply sloping rocksnear waterfall in upper part of ravine, 1992, B. J.Coppins (15368) et al.(E).—Svalbard: Ytre Norskøya:17 vii 1928, Högn (TRH).—USA: Maine: PiscataquisCo., Baxter State Park, Mt. Katahdin, South Basin,Waterfall Gully, 45(54#23$N, 68(54#51$W, 1190 m,on a large flushed slab of near-vertical granite, 2001, J.Hinds 4629 (MAINE).

Porpidia thomsonii Gowan

Bryologist 92: 54 (1989): type: Canada, NorthwestTerritories. Keewatin District, south end of DubawntLake, Thomson 20416 (WIS—holotype!).

Gowan (1989a) described P. thomsonii asintermediate between P. crustulata and P.macrocarpa, with respect to apothecia andascospore size, height of hymenium, andwidth of excipular hyphae. However, asshown above (under P. macrocarpa) thesecharacters, especially the width of excipularhyphae, vary with the size of the apotheciawithin a single specimen and are insufficientjustification for describing a new specieswith intermediate characters. However, theexcipular hyphae of mature apothecia of theholotype of P. thomsonii are wider than isusual for even small apothecia in this groupof species (5–8·5 �m wide), and the medullaof the exciple is distinctly paler and has abrown colouration that contrasts sharplywith the blue-black cortex. It is probable thatP. thomsonii is a good species, although thediagnosis given by Gowan is insufficient tofully characterize it and further work isrequired to identify the critical differencesthat separate it from P. macrocarpa.

The holotype of P. thomsonii, and severalother collections annotated as that speciesby Gowan, have the same wide (0·1 mm)proper exciple as P. macrocarpa, to which P.thomsonii is clearly closely related. However,other collections identified as this species byGowan do not share the characters of the


holotype, and although Gowan & Ahti(1993) reported P. thomsonii from easternFennoscandia I have not seen their speci-mens so cannot say whether they are con-specific with the holotype, although there isno reason why it should not occur there.Only two collections referable to P. thomsoniihave been identified among collections fromthe British Isles but it is probably not rareat high altitude in the Scottish Highlands.It apparently occupies the same habit asP. striata and is similar to that species,from which it differs in having a smoothproper margin and the exciple lacking acarbonaceous cortex.

Specimens examined. Great Britain: Scotland: V.C.98, Argyll Main: Glen Etive, Ben Starav, 27/1342,850 m, granite rock in alpine heath, 1991, Fryday 2336(E). V.C. 97, West Inverness-shire: Ben Nevis range,Aonach Mór, summit plateau, 27/1972(–3), 1150–1221 (c. 1200) m, small stones, 1990, B. J. Coppins(13792), A. M. Fryday & O. L. Gilbert (E).—Canada:Yukon Territory: ‘‘Brewster Service’’, Mile 96 HainesHwy, 60(14#N, 136(59#W, 3000–5000 ft, on pebbleson soil mound in the open, 1967, J. W. Thomson(22992) & T. Ahti (CANL); Frances Lake Area,Mt. Billings, 61(10#N, 128(59#W, 1830 m, inblockfield near summit, 1982, R. Rosie 776 (CANL).Alberta: Waterton Lakes National Park, Cameron Laketo Carthew Summit, 1963, G. W. Scooter 4520(CANL).

Porpidia zeoroides (Anzi) Knoph &Hertel

In Hertel & Knoph, Mitt. Bot. Staatssamml. München20: 477 (1984).—Lecidea zeoroides Anzi, Comment. Soc.Critt. Ital. 2: 17 (1864); type; Italy (Anzi, Lich. Lang.357; M—isotype, n.v.).

This species occurs on basic rocks anddiffers from P. superba in having black apoth-ecia with a white pruinose outer rim to theproper margin, and olivaceous pigment(Macrocarpa-green) in the epihymenium.The exciple and/or hypothecium also havepatches of fine granular inclusions that donot dissolve in K or N, and which make thestructure difficult to discern. Porpidia zeor-oides appears to be more closely related to P.macrocarpa than to P. superba. In the BritishIsles it is known from only two localities inthe Central Highlands (Fryday 1996b).

Specimens examined. Great Britain: Scotland: V.C.88, Mid Perthshire: Ben Lawers, opposite CreagLoisgte, 27/6341, 1050 m, west-facing folded mica-schist rock-face, 1995, Fryday 6038 (pt E). V.C.98, Argyll Main: Loch Creran, west ridge of BenSgulaird, 27/027450, 525 m, on mica-schist/metamorphosed LST outcrop, 1995, Fryday (6090,6101) & R. Leishman.

The Porpidia speirea group

Porpidia flavicunda (Ach.) Gowan

Bryologist 92: 43 (1989).—Lecidea flavicunda Ach., Lich.Univ.: 166 (1810); type: Switzerland, Schleicher 376(H-ACH—holotype!).

Lecidea flavo-coerulescens1 Hornem., Fl. Dan. 8, fasc.24: 5, tab. 1431, fig. 1 (1810), nom. utique rej. prop.—Porpidia flavocaerulescens (Hornem.) Hertel & A. J.Schwab, in Hertel, Beih. Nova Hedwigia 79: 437(1984); type: Norway, Upper Telemark, Smith (FloraDanica tab. 1431, fig. 1—lectotype!).

The name Lecidea flavocoerulescens is basedon the original description and illustration ofthat taxon in Flora Danica (http://www.pictures.dnlb.dk/FloraDanica/Hefte24/www/1431.jpg). Gowan & Ahti (1993) in-vestigated the nomenclature of the orangespecies of Porpidia and showed that, as thatillustration clearly showed an esorediatetaxon, the sorediate lectotype chosen byHertel (1977) was in serious conflict withthe protologue (ICBN Art. 9.17b; Greuteret al. 2000) and had to be rejected. InsteadGowan & Ahti (op cit.) chose the illustrationin Flora Danica as the lectotype, thus asso-ciating the name with the esorediate taxon,and further showed that the name P. melin-odes (Körber) Gowan & Ahti was availablefor the sorediate taxon.

However, although the illustration inFlora Danica is sufficient to show that thename Lecidea flavocoerulescens must be as-sociated with an esorediate taxon, it is insuf-ficient to show which esorediate taxon that1In Flora Danica, Hornmann spelled the specific epithetflavo-coerulescens, and as this spelling is given as analternative to the more usual flavo-caerulescens by, forexample, Stearn (1992) it should be retained as anorthographic variant, rather than considered an ortho-graphic error and ‘corrected’ to flavocaerulescens. Theconfusion appears to have arisen because Acharius(1814) spelled the name flavo-caerulescens when he tookup the name in Synopsis Methodica Lichenum.


should be. The illustration shows a crustoselichen with only a lightly, partly oxydatedthallus that is only dubiously referable to thespecies currently known as Porpidia flavo-coerulescens. It is more likely to represent aspecies of Lecidea or Porpidia with a grey,partly oxydated thallus (possibly Porpidiamacrocarpa, Lecidea lithophila or L. lapicida).Even if the illustration is considered to be ofan esorediate species of Porpidia with anobligate, orange thallus, it is impossible todetermine whether it represents P. flavo-coerulescens or P. flavocruenta.

Therefore, there are several good reasonswhy the name should be formally rejected:

1 the application of the name is confused;it has been applied to the sorediate (e.g.Inoue 1983; Gowan 1989a), esorediate(Lynge 1939; Magnusson 1952a, b;Wirth 1980) or both morphotypes(Degelius 1937, 1983; Hertel 1977;Clauzade & Roux 1986; Schwab 1986).

2 Porpidia flavocoerulescens is indistin-guishable macroscopically from P. flav-ocruenta so it will be necessary to choosean epitype to establish the correctapplication of the name Lecidea flavo-coerulescens.

3 the delimitation of P. flavocoerulescens isstill unclear because both morphologi-cal (e.g. thickness of hypothecium,length of conidia, etc) and molecularcharacters (J. Buschbom pers. comm.),suggest that P. flavocoerulescens com-prises at least two, closely relatedlineages.

4 the illustration and description in FloraDanica constitute only a rudimentarydescription from which it is impossibleto determine the identity of the taxonbeing described.

5 there is a readily available alternativename, L. flavicunda Ach., published inthe same year as L. flavocoerulescens, forwhich there is a good, well-developedholotype with apothecia and pycnidia.

Given the confusion of the application ofthe name, the need to select an epitype if thename is accepted, and the availability of asuitable alternative, it would appear that the

wisest course of action is to propose formalrejection of the name (Fryday 2005).

Most records of P. flavicunda from theBritish Isles are referable to P. flavocruenta(see above), although there are Britishcollections of P. flavicunda from Scotland(East Ross, East Sutherland) and Ireland(South Kerry), and the taxon is probablywidespread, although uncommon.

Selected material examined. Great Britain: Scotland:V.C. 106, East Ross-shire: 17 km ESE of Ullapool,crags W of Loch a’ Choire Mhòir, 28/3188, 450 m,large boulder near base of cliff, 1984, B. J. Coppins(10946) et al. (E); V.C. 107, East Sutherland: BenGriam Beg, 29/8340, 460–490 m, shoulder SE of sum-mit, 1999, B. J. Coppins (18888) et al. (E).—Ireland:[V.C. H1, South Kerry:] Dunkerron, Taylor (BM);ibid., Dingle Peninsula, Connor’s Pass, Lough Doon,01/5006, 500 m, sandstone boulder, 1994, A. M.Fryday (5212) & O. L. Gilbert.—Svalbard: Bjørndalen:2003, T. Tønsberg (BG).—USA: Alaska: Mt McKinleyNP, NW slope to summit of Mt Eieson (Copper Mt),63(25#N, 50(20#W, 1050–1660 m, moist tundra, fell-field, knife-edge ridge, 1956, W. A. Weber & L. A.Viereck S 7009A (MSC); North Slope, one mile northof Jago Lake, 143(45#W, 69(28#N, between frost boilson rock, 1958, J. E. Cantlon & W. T. Gillis 58–645(MSC).

Porpidia grisea Gowan

Bryologist 92: 48 (1989): type: USA, Alaska Valley ofthe Okpilak River at Okpilak lake near Mt Michelson,Thomson 10218 (WIS—holotype!).

Gowan (1989a) described material resem-bling non-sorediate, fertile P. tuberculosa as adistinct species, P. grisea. The holotype ofP. grisea (in WIS) has a thallus of dispersedareoles on a black hypothallus with sessileapothecia, and molecular data (Buschbom &Mueller 2004) clearly separated a specimenidentified as P. grisea from one identified asP. tuberculosa, suggesting that more than oneentity is present. Consequently, at this stage,I prefer to retain the two names, pending amore detailed investigation to determine thebasis for distinguishing between them. Theseparation of these two species is discussedin more detail under P. tuberculosa.

No specimens from the British Isles havebeen found that are referable to P. grisea;all previous reports being based onmisidentifications of other species.


Porpidia melinodes (Körb.) Gowan &Ahti

Ann. Bot. Fennici 30: 67 (1993).—Aspicilia melinodesKörb. Sitzungsber. kaiserl. Akad. Wiss. Math.—Naturwiss Cl. Abt. 1, 71: 3 (1872); type: Spitzbergen,(M—neotype, n.v.).

Gowan & Ahti (1993) discussed thisspecies and the closely related P. flavicunda(as P. flavocoerulescens) in some detail, show-ing that the name P. flavocoerulescens re-ferred to the non-sorediate taxon and that P.melinodes was available for the sorediate one.They also concluded that two separatespecies were involved, based mainly on thethinner thallus of P. melinodes and the differ-ent secondary chemotypes that occur; theprimary chemotype of both taxa containingconfluentic acid. However, molecular data(Buschbom & Mueller 2004) indicates thatP. melinodes and P. flavicunda are veryclosely related, and other species pairswithin Porpidia also have a thinner thalluswhen sorediate (e.g. P. superba) and so thisdifference should probably be treated withcaution. The situation is further complicatedby the fact that it is now known that morethan one species has been included underP. flavicunda (see above, and under P. flav-ocruenta) and it is unclear to which Gowan &Ahti were referring.

A wide view of this species is taken here,including in it any member of the P. speireagroup with an obligate orange thallus thatproduces soredia, including those specimensthat are abundantly fertile. A single collec-tion from a wall at a disused metal mine atStrontian, Argyll (Fryday 3163), has anorange thallus that lacks lichen substancesby TLC, blue-grey soredia, and apotheciawith a bright aeruginose epihymenium(Cinereorufa-green). It has a dark exciplecomposed of narrow hyphae 3–4 �m wide,suggesting that it is a member of the P.speirea group and closest to P. melinodes.However, it differs from that species inhaving an aeruginose epihymenium and athallus lacking lichen substances.

Selected material examined. Great Britain: England:[V.C. 40,] Shropshire: Titterstone Clee Hill, [32/5977],Salwey (BM). Scotland: V.C. 88, Mid Perthshire: Killin,

Sròn a’Chlachain, 27/5532, 475 m, iron-rich rock inwall, 1990, Fryday 1451; ibid., Forest of Mamlorn, AlltBatavaim, 27/411359, 600 m, shaded rock by burn,1991, Fryday 2322. V.C. 94, Banffshire: 7 km SE ofTomintoul, Coire Buidhe, ‘Ironstone Mine’, 38/138160, 485 m, on iron-rich rocks, 1984, B. J. Coppins(10642) et al. (E). V.C. 96, East Inverness-shire: LochNess, nr Invermoriston, [28/41], boulders, 1942, U.Duncan (BM), Glen Strathfarrar, N side of Locha’Mhuillidh, 28/273384, c. 140 m, on iron-rich boul-der, 1985, B. J. Coppins 11126 (E). V.C. 103, MidEbudes: Isle of Mull, south side of Loch na Keal,Scarisdale Wood [17/5238], on a big boulder bythe road, 1954, Lindahl 128a (E). V.C. 106, EastRoss-shire: 17 km ESE of Ullapool, crags W of Loch a’Choire Mhòir, 28/3188, 450 m, large boulder near baseof cliff, 1984, B. J. Coppins (10947) et al. (E,BM).—Ireland: [V.C. H39, Antrim:] Antrim Mts,Moore. (E)—Sweden: Lycksele Lappmark: Tärna, LakeStor-Björkvattnet, by the stream Gejmån, 65(35#N,15(00#W, 420 m, on rock, close to a stream in a Picea-dominated forest, 2003, P. G. Ihlen 1196 (MSC).

Porpidia speirea (Ach.) Kremp.

Denkschr. Kgl. bayer. Bot. Ges. 4(2): 210 (1861).—Lichen speireus Ach., Lich. Svec. Prodr. 59 (1799[‘1798’]); type: Sweden (UPS—neotype, n.v.).

This is one of the few species of Porpidiathat occurs exclusively on calcareous rocks.Within the genus it is likely to be confusedonly with the rare P. trullisata (known onlyfrom the Alps), which contains stictic notconfluentic acid.

The chalky white thallus, and innateapothecia give P. speirea a superficial resem-blance to some species of Rhizocarpon (e.g.R. chioneum, R. petraeum and R. umbilica-tum), from which it is easily distinguishedmicroscopically by its simple ascospores.

Selected material examined. Great Britain: Scotland:V.C. 88, Mid Perthshire: Ben Lawers NNR, Creag nanGabhar, 27/6240, 950 m, slightly basic mica-schistcrags, 29 vi 1989, Fryday s.n.; Ben Lawers, SE ridge,27/6341, 1200 m, mica-schist boulder, 1990, Fryday1298; Glen Lochay, Meall nan Subh, 27/4539, 775 m,shaded, slightly basic rock, 1991, Fryday 2113. V.C.103, Mid Ebudes: Isle of Mull, Ardmeanach, Burg,17/4027, 150 m, basalt crag, 1993, Fryday 4433.

Porpidia tuberculosa (Sm.) Hertel &Knoph

In Hertel, Beih. Nova Hedwigia 79: 438 (1984).—Spiloma tuberculosa Sm, in Smith & Sowerby, Eng. Bot36: tab 2556 1814; type; Britain, Newcastle, Robertson,


Eng. Bot 36: tab. 2556 1814 (lectotype—designatedhere).

Smith’s description is comprehensive andhe is clearly describing a sorediate, crustosespecies. However, because the species cur-rently referred to as Porpidia tuberculosa ischaracterized by having a thallus containingconfluentic acid and an amyloid (I+ blue)medulla, and there are a number of othertaxa that fit Smith’s description equally well(e.g. Lecanora pannonica, Porpidia soredi-zodes, Tephromela grumosa), it is impossibleto be certain that this is the species Smithwas describing. Robertson’s original collec-tion of Spiloma tuberculosa could not befound in BM or HAMU, and there is a noteattached to Sowerby’s original plate that saysthat the specimen is ‘‘apparently not now inexistence’’ (S. LaGreca pers. comm.). Thereare two collections filed under Spilomatuberculosa in the Robertson collection inHAMU, but both were collected in Cumbria(Ashness Gill and Coniston) in July 1824 (L.Jessop pers. comm.) and so cannot be con-sidered as type material. The illustration inEnglish Botany must be considered part ofthe original material (ICBN Art. 9.2, note2a; Greuter et al. 2000) and, because itis the only element now in existence, it ishere designated as the lectotype. However,it will probably be necessary to selectan epitype to fix the name on its currentapplication.

Specimens of P. tuberculosa from themountains of the western highlands ofScotland usually have a thick thallus and,commonly, support both apothecia andsoredia. Molecular data (Buschbom &Mueller 2004; J. Buschbom unpublished)suggests that more than one entity is in-volved in the P. tuberculosa complex, and it ispossible that the morphotype with a thickthallus may be a distinct taxon more closelyrelated to, or conspecific with P. grisea.However, at this stage, it is unclear whetherthe sorediate specimens with a thick thallusbelong to P. grisea or P. tuberculosa, and so Ihave provisionally retained all sorediatespecimens in P. tuberculosa.

Specimens from the vicinity of areas oflate snow-lie in the, more continental,Cairngorm Mountains have a thinnerthallus, which corresponds with typical P.tuberculosa from lowland areas. It wouldappear that the entity with the thick thallushas its primary habitat in low alpine, oceanicregions, with the sorediate entity occurringat both higher and lower altitudes and inmore continental areas.

Selected material examined. Great Britain: Wales:V.C. 46, Cardiganshire (Ceridigion): Plynlimon mine,22/794857, 550 m, block spoil from mine, 1994, Fryday(5006), S. P. Chambers & R. G. Woods. Scotland: V.C.88, Mid Perthshire: Ben Lawers NNR, Creag anLochain, 27/5941, 650 m, shaded underhang on acidcrags, 1991, Fryday 2079; Killin, Beinn Leabhain,27/5728, 650 m, acid rocks, 1992, Fryday 3021.

The Porpidia albocaerulescens group

Porpidia albocaerulescens (Wulfen)Hertel & Knoph

The species has not been correctly recordedfrom NW Europe, previous records beingmisidentifications of other species of thegenus, mainly P. cinereoatra (Purvis et al.1993) or P. macrocarpa (Santesson 1993).Porpidia albocaerulescens is a species ofsiliceous rocks in damp habitats in moresouthern, continental regions, for exampleCentral Europe (Hertel & Knoph 1984) andeastern North America (Gowan 1989a).

Porpidia glaucophaea (Körb.) Hertel &Knoph—see P. rugosa.

Porpidia hydrophila (Fr.) Hertel &A. J. Schwab

In Hertel, Beih. Nova Hedwigia 79: 437 (1984).—Lecidea hydrophila Fr. Kungl. Vetensk. Akad Nya Handl256 (1822); type: Sweden, Småland, Femsjö ?E. Fries(UPS—lectotype, n.v., fide Inoue 1979).

This species is readily distinguished fromall other described species of Porpidia by itsbright aeruginose (Cinereorufa-green) epi-hymenium (but see above under P. melin-odes). The exciple of P. hydrophila has adark, �carbonaceous cortex with a muchpaler, pale brown interior composed of


filamentous hyphae 2–4 �m wide, indicatingthat it belongs in the P. albocaerulescens-group. This is supported by its conidia,which are (8·0–) 9·0–12·0 �m long (8–9–10·3–13 �m in P. albocaerulescens (Rambold1989)), and its habitat of damp rocks.

Selected additional specimens examined. Great Brit-ain: Wales: [V.C.49 Caernarfonshire:] Penygwryd, [22/6555,] June 1865, W. A. Leighton (BM). Scotland: V.C.88, Mid Perthshire: Glen Lyon, Meall Ghaordaidh,Creag Laoghain, 27/5140, c. 550 m, 1991, Fryday2288. V.C. 101, Kintyre: 5 km SW of Skipness, Claon-aig Wood SSSI (Coille Rubha Duibh), 16/8655,0–60 m, on boulder in stream, 1994, B. J. Coppins(16264) & A. M. O’Dare (E).—Ireland: [V.C. H1,South Kerry:] Dunkerron, T. Taylor (BM).

Porpidia rugosa (Taylor) Coppins &Fryday comb. nov.

Endocarpon rugosum Taylor, in Mackay, Flora Hibernica2: 258 (1836); type: Ireland, Dunkerron mountain,1836, T. Taylor (FH—holotype!).

Lecidea glaucophaea Körb., Parerga Lich.: 222(1861).—Porpidia glaucophaea (Körb.) Hertel &Knoph, in Hertel, Beih. Nova Hedwigia 79: 437 (1984);type: not designated.

Taylor (1836) described the new speciesEndocarpon rugosum from Dunkerron moun-tain, Kerry, Ireland. The holotype (in FH) isin good condition, has a thick tartareous,sorediate thallus containing the 2#-O-methylsuperphyllinic acid chemosyndrome,and is clearly referable to the species cur-rently known as P. glaucophaea. Taylor’sdescription predates Körber’s by 25 yearsand as we consider the existence of a goodholotype of a taxon to be more importantthan nomenclatural stability for a speciesthat is not particularly common or wide-spread, and as no original material ofKörber’s species could be found in L(Gowan 1989a), where Körber’s herbariumis housed, we do not consider it appropriateto conserve Porpidia glaucophaea by propos-ing E. rugosum for formal rejection. Weaccordingly make the new combinationPorpidia rugosa for this species.

Sorediate specimens of Porpidia that con-tain the 2#-O-methylsuperphyllinic acidchemosyndrome in their thallus are usuallyreferred to this taxon. Two morphotypes are

known; one has a thin thallus that often hasa greenish tinge, has soralia developing inlines along cracks in the thallus, and occurson siliceous rocks, whereas the other, whichincludes the holotype, has a thick, white,tartareous thallus, with �rounded or irregu-lar soralia not developing from cracks in thethallus, and usually occurs on slightly basicrocks. The morph with the thinner thallusis frequent in Central Europe, and in theBritish Isles occurs in damp habitats (oftennear water), whereas the morph with thethicker thallus is common in Scandinavia,and in the British Isles most often occurson flushed, vertical, weakly basic rock inmountainous areas. The original descriptionof Lecidea glaucophaea (Körber 1865) refersto the thallus as ‘tenuis tartareus’ but Gowan(1989a) was unable to locate any of theoriginal material upon which the descriptionwas based. Gowan & Ahti (1993) com-mented on the wide variation in thallusmorphology and suggested that more thanone entity may be involved. I was, at first,tempted to treat the two morphotypes asseparate species, but two specimens fromSW Ireland (Fryday 5204–5) show a grada-tion between the two morphs and so, atthis stage, I prefer to keep them as a singletaxon.

The apothecia of P. rugosa appear to beidentical to those of P. albocaerulescens, theonly difference between the two speciesbeing primary means of reproduction,thalline chemistry, and distribution (seeTable 4). However, the presence of a sore-diate morph of P. albocaerulescens in easternNorth America, and the description byGowan (1989a) of the non-sorediate, fertileNorth American west coast population con-taining 2#-O-methylsuperphyllinic as a dis-tinct species (P. carlottiana Gowan), narrowsthe distinction between P. albocaerulescensand P. rugosa even further. The species alsohas a more variable chemistry than is usuallyreported; collections containing confluenticacid (Fryday 2189) and methyl 2#-O-methylmicrophyllinate (Fryday 3374) hav-ing been made from the BreadalbaneMountains in the Central Highlands ofScotland.


The P. albocaerulescens complex is in needof further study. Gowan (1989a) suggestedthat it was probably worthy of generic rank,and this opinion is supported by molecularevidence (Buschbom & Mueller 2004).

Selected material examined. Great Britain: Scotland:V.C. 88, Mid Perthshire: Beinn Heasgarnich, Crag nah-Achlarich, 27/4238, 750 m, damp (vertical) acidrock, 1991, Fryday 2157; ibid., Creag nam Bodach,damp acid crag, 27/4437, 650 m., 1991, Fryday 2189(with confluentic acid); Killin, Glen Lochay, 27/5335,

125 m, acid crag in wood, 1992, Fryday 3085; ibid.,exposed mica-schist boulder, 1992, Fryday 3374 (withmethyl 2#-O-methylmicrophyllinate). V.C. 103, MidEbudes: Isle of Mull, Ardmeanach, Burg, 17/4027,150 m, basalt crag, 1993, Fryday 4437.—Ireland:V.C. H1, South Kerry: Dingle Peninsula, Connar’sPass, Lough Doon, 01/5006, 500 m, damp boulder,1994, Fryday (5204) & O. L. Gilbert; ibid., vertical cragabove loch, 1994, Fryday (5205) & O. L. Gilbert;Dingle Peninsula, Mount Brandon, 01/4711, 500 m,�dry vertical sandstone crag, 1994, Fryday (5239) &O. L. Gilbert.

Provisional key to the species of Porpidia occurring in the British Isles

The following key must be considered provisional because the taxonomy of the genus is stillvery fluid, and species concepts will undoubtedly change significantly in the future. Inparticular, species which have a more variable chemistry than previously reported may notkey out correctly. The result obtained from using the key should always be checked with thefull description provided above. The main diagnostic characters of the taxa are tabulated inTable 4.

1 Thallus with papillose isidia; containing stictic acid (K+ yellow, Pd+ orange).Known only from serpentine rocks . . . . . . . . . . . . . P. nadvornikiana

Thallus not isidiate. Chemistry and substratum various . . . . . . . . . . . . . 2

2(1) Thallus with soredia, apothecia present or absent . . . . . . . . . . . . . . . . 3Thallus without soredia, apothecia present . . . . . . . . . . . . . . . . . . . 11

3(2) Medulla I+ blue . . . . . . . . . . . . . . . . . . . . . . . . . P. tuberculosaMedulla I� . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4(3) Thallus orange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Thallus grey, sometimes partly oxydated . . . . . . . . . . . . . . . . . . . . . 7

5(4) Thallus thin, cracked-rimose, pale creamy orange; stictic acid present (K+ yellow,Pd+ orange). On damp rocks, usually beside streams . . . . P. ochrolemma

Thallus areolate; stictic acid usually absent (K�, Pd�); if present then conflu-entic acid (K+ numerous ‘oil droplets’ in section) also present . . . . . . . 6

6(5) Epihymenium vivid aeruginose (Cinereorufa-green). Lichen substances absent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. aff. melinodes

Epihymenium olivaceous brown (Macrocarpa-green). Thallus usually containingconfluentic acid (K+ numerous ‘oil droplets’ in section), although otherchemotypes (2#-O-methylperlatolic acid, norstictic acid) have been reported

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. melinodes

7(5) Thallus containing stictic acid (K+ yellow, Pd+ orange), or rarely with no lichensubstances present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Stictic acid absent (K�, Pd�). Confluentic acid, methyl 2#-O-methylmicrophyllinate, or 2#-O-methylsuperphyllinic acid present . . . . . . 9

8(7) On basic or flushed rocks in upland/montane areas. Thallus, continuous-cracked,creamy white. Soralia usually raised. Apothecia with constricted base and browndisc . . . . . . . . . . . . . . . . . . . . . . . . . . P. superba f. sorediata

On siliceous rocks in lowland areas. Soralia usually tuberculate. Apothecia sessilewith black disc . . . . . . . . . . . . . . . . . . . . . . . . . P. soredizoides


T 4. Main diagnostic characters for species of Porpidia recorded from NW Europe

TaxonOrangethallus

Soredia/isidiapresent

Apotheciainnate

Albocaerulescens-type

excipleSecondary metabolite

chemosyndrome*

Epihymeniumpigment not

Macrocarpa-greenor Arnoldiana-brown

Onbasicrocks

MedullaI+ blue Other characters

P. albocaerulescens — — innate yes stictic acid — — —P. cinereoatra — — innate — confluentic acid — — —P. contraponenda — — — — m 2#-O-mmp — — —P. aff. contraponenda — soredia — — m 2#-O-mmp — — —P. crustulata — — — — stictic acid

none— — — margin <0·08 mm wide

P. flavicunda orange — — — confluentic acid?norstictic acid

— — —

P. flavocruenta orange — — — none — — — exciple K+ crimsonP. grisea — — — — confluentic acid — — medulla I+ blueP. hydrophila — — — yes none Cinereorufa-green — —P. islandica — — — — none — �basic — paraphyses with distinct capsP. lowiana — — — — confluentic acid — — —P. macrocarpa

f. macrocarpa— — — — none

stictic acid— — — margin up to 2 mm wide

f. nigrocruenta — — — — nonestictic acid

— — — exciple K+ crimson

P. melinodes orange soredia — — confluentic acid2#-O-mplnorstictic acid

— — —

P. aff. melinodes orange soredia — — none Cinereorufa-green — —P. nadvornikiana — isidia — — stictic — — —P. ochrolemma orange soredia — — stictic — — — thallus rimoseP. pachythallina — soredia — — confluentic acid — — —P. platycarpoides — — — — norstictic acid

stictic acid— —

P. rugosa — soredia — yes 2#-O-mspm 2#-O-mmpconfluentic acid

— — —

P. soredizoides — soredia — — stictic acid — — —P. speirea — — innate — confluentic acid — basic medulla I+ blueP. striata — — — — none — — — radially striate marginP. superba — — — — stictic acid

noneSuperba-brown basic —

P. superba f. sorediata — soredia — — stictic acid Superba-brown basic —P. thomsonii — — — — none

stictic acid— — —

P. tuberculosa — soredia innate — confluentic acid — — medulla I+ blueP. zeoroides — — — — stictic acid

none— basic —

*m 2#-O-mmp=methyl 2#-O-methylmicrophyllinate; 2#-O-mpl=2#-O-methylperlatolic acid; 2#-O-msp=2#-O-methylsuperphyllinic acid.

2005P

orpidia—F

ryday31

9(7) Confluentic acid present (K+ numerous ‘oil droplets’ in section). Thallus whitishto grey; soredia blue-grey. On exposed montane rocks . . P. pachythallina

Confluentic acid absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

10(9) Methyl 2#-O-methylmicrophyllinate present. Thallus usually thin, soredia round-ish. Exciple of apothecia in section �uniformly dark P. aff. contraponenda

2#-O-methylsuperphyllinic acid present. Thallus often thick and tartareous, if thinthen soredia linear. Exciple of apothecia in section with a dark pigmented cortexand �hyaline medulla . . . . . . . . . . . . . . . . . . . . . . . P. rugosa

11(2) Exciple of apothecia in section with a dark pigmented cortex and �hyalinemedulla composed of thin filamentous hyphae 2–3 �m wide (albocaerulescens-type) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Exciple of apothecia with pigmented medulla, usually composed of thickerpseudoparenchymatous hyphae 3–8 �m wide; if hyphae thinner then medulla not�hyaline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

12(11) Epihymenium vivid aeruginose (Cinereorufa-green). Usually on �semi-inundated, siliceous rocks . . . . . . . . . . . . . . . . . . . . P. hydrophila

Epihymenium brown (Arnoldiana-brown) or olivaceous (Macrocarpa-green) 13

13(11) Apothecia usually innate. Thallus and apothecium exciple containing stictic acid(K+ yellow, Pd+ orange). Not correctly reported from the British Isles orScandinavia . . . . . . . . . . . . . . . . . . . . . . . P. albocaerulescens

Apothecia sessile. Thallus and apothecia not containing stictic acid, usuallycontaining 2#-O-methylsuperphyllinic acid, but rarely with methyl 2#-O-methylmicrophyllinate or confluentic acid . . . . . . . . . . . . . P. rugosa

14(11) Medulla I+ blue, thallus with confluentic acid present (K+ numerous ‘oil droplets’in section) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Medulla I�; thallus with confluentic acid or not . . . . . . . . . . . . . . . 16

15(14) On �basic rocks, thallus white, apothecia innate . . . . . . . . . . P. speireaOn siliceous rocks, thallus grey, apothecia usually sessile. Not correctly reported

from the British Isles . . . . . . . . . . . . . . . . . . . . . . . . . P. grisea

16(14) Thallus orange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Thallus grey, sometimes partly oxydated . . . . . . . . . . . . . . . . . . . . 18

17(16) Excipular hyphae 5–8·5 �m wide; usually with K+ crimson pigment. Thalluslacking lichen substances . . . . . . . . . . . . . . . . . . . P. flavocruenta

Excipular hyphae 3–4 �m wide; without K+ crimson pigment. Thallus usuallycontaining confluentic acid, although a chemotype with norstictic acid has alsobeen reported . . . . . . . . . . . . . . . . . . . . . . . . . . P. flavicunda

18(16) Epihymenium and exciple with only orange-brown pigment (Superba-brown);exciple intensifying in N and 15% HCl, but without reddish colouration;exciple medulla dark orange-brown (N and 15% HCl paler orange) withdark brown cortex. Apothecia�strongly constricted below, disc usually brownwith a thick raised margin. Ascospores usually >20 �m long. Thallus white,usually bullate, but occasionally smoother. Usually on basic rocks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. superba f. superbaEpihymenium and/or exciple cortex with olivaceous (Macrocarpa-green), or brown

(Arnoldiana-brown) pigments (N+ reddish) . . . . . . . . . . . . . . . . . 19


19(18) On �basic rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20On siliceous rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

20(19) Apothecia constricted at the base; white pruina on outer rim of proper margin.Internally, exciple and/or hypothecium with numerous granular inclusions notdissolving in K or N. Epihymenium with olivaceous pigment (Macrocarpa-green). Paraphyses without well developed pigmented tips . . . P. zeoroides

Apothecia �adnate to sessile, not constricted at base; proper margin without whitepruina. Epihymenium with only brown pigments. Paraphyses with well-developed, pigmented tips . . . . . . . . . . . . . . . . . . . . . P. islandica

21(20) Exciple dark, with paler medulla apparent only in thin section. Thallus epilithic,containing confluentic acid or methyl 2#-O-methylmicrophyllinate . . . . . 22

Exciple not uniformly dark in section. Thallus often endolithic, containing sticticacid, norstictic acid, or no substances (K+ red or yellow or K�) . . . . . 24

22(21) Apothecia usually innate, becoming convex, with thin (c. 0·05 mm) barely raisedmargin. Thallus thick, cracked-areolate, usually continuous; containing conflu-entic acid (K+ numerous ‘oil droplets’ in section) . . . . . . P. cinereoatra

Apothecia sessile with thick (c. 0·1 mm) raised, persistent margin. Thallus thinner,often composed of �dispersed areoles; containing methyl 2#-O-methylmicrophyllinate or confluentic acid . . . . . . . . . . . . . . . . . . 23

23(22) Thallus containing methyl 2#-O-methylmicrophyllinate (K�). Apothecia rarelypruinose . . . . . . . . . . . . . . . . . . . . . . . . . . P. contraponenda

Thallus containing confluentic acid (K+ numerous ‘oil droplets’ in section).Apothecia often pruinose . . . . . . . . . . . . . . . . . . . . . . P. lowiana

24(21) Proper margin thin and barely raised, <0·08 mm wide. Mature apothecia <1·5 mmdiam. Thallus thin, usually containing stictic acid (K+ yellow, Pd+ orange).Exciple �uniformly pale brown internally. Ascospores 12–16(–18) �m long,hymenium 70–90 �m high . . . . . . . . . . . . . . . . . . . P. crustulata

Proper margin thick and raised, >0·1 mm wide. Mature apothecia >1·5 mm diam.Exciple pale- to mid-brown internally. Thallus endolithic to moderately thick,containing norstictic acid (K+ red, Pd+ yellow), stictic acid (K+ yellow, Pd+orange), or no substances. Ascospores 16–18(–21) �m long, hymenium 90–110 �m high (P. macrocarpa aggr.) . . . . . . . . . . . . . . . . . . . . . . 25

25(24) Thallus and exciple K+ red (norstictic acid) or rarely K+ yellow (stictic acid).Thallus epilithic, white. Apothecia densely pruinose; medulla of exciple verypale. Usually maritime, but also in montane areas . . . . . P. platycarpoides

Thallus and exciple K+ yellow or K� (stictic acid or no substances present).Thallus often endolithic. Apothecia not or only slightly pruinose; medulla ofexciple pale brown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

26(25) Proper exciple persistent, radially striate. Internally, exciple with a cracked,carbonaceous cortex. Thallus lacking lichen substances . . . . . . . P. striata

Proper exciple �smooth (at most flexuose). Internally without carbonaceouscortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

27(26) Apothecia <1·5 mm diam (usually <1·1 mm), proper margin c. 0·1 mm wide.Exciple composed of swollen elongate cells 5–8(–10) �m wide P. thomsonii

Apothecia up to 3·0 mm diam., margin up to 0·2 mm wide. Exciple composed ofcells 4–6(–8) �m wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28


28(27) Exciple reacting K+ crimson solution . . . . P. macrocarpa f. nigrocruentaExciple not reacting K+ crimson solution . . P. macrocarpa f. macrocarpa

I am particularly grateful to Dr Jutta Buschbom(Chicago/Düsseldorf) for sharing the results of hermolecular work on Porpidia. Without her co-operation,and numerous useful discussions on clarifying speciesconcepts within the genus, this contribution wouldnever have been completed. I also gratefully acknowl-edge support from US National Science Foundation,Award No. DBI–9808 735 (Alan Prather, PI) to Michi-gan State University, which allowed Dr Buschbom tovisit Michigan State University, and a research scholar-ship from The Field Museum of Natural History,Chicago, which permitted me to visit the Field Museumand work with Dr Buschbom. I also thank ProfessorsTuevo Ahti (Helsinki) and Per Magnus Jørgensen(Bergen) for advise on nomenclatural matters, Dr BrianCoppins (Edinburgh) for correcting my Latin diag-noses, the curators of BM, CANL, E, F, G, H, L, M,MICH, MIN, MSC and WIS for the loan of material intheir care, and Professor Mark Seaward (Bradford) forproviding the maps for Fig. 5.

R

Acharius, E. (1814) Synopsis Methodica Lichenum.Lund: Svanborg.

Buschbom, J. & Mueller, G. (2004) Resolving evolu-tionary relationships in the lichen-forming genusPorpidia and related allies (Porpidiaceae, Ascomy-cota). Molecular Phylogenetics and Evolution 32:66–82.

Clauzade, G. & Roux, C (1986) (‘1985’) Likenoj deOkcidenta Europo. Ilustrita Determinlibro. Bull-etin de la Société Botanique du Centre-Ouest, NouvelleSérie, Numéro Spécial 7. Royan, France.

Coppins, B. J. (2002) Checklist of British and IrishLichens. London: British Lichen Society.

Degelius, G. (1937) Lichens from southern Alaska andthe Aleuthian Islands, collected by Dr. E. Hultén.Meddelelser fran Göteborgs Botaniska Trädgard 12:105–144.

Degelius, G. (1983) (‘1982’) The lichen flora of theisland of Vega in Nordland, northern Norway. ActaRegiae Societatis Scientiarum et Litterarum Gothober-gensis, Botanica 2: 1–127.

Esslinger, T. L. & R. S. Egan. (1995) A sixth checklistof the lichen-forming, lichenicolous, and alliedfungi of the continental United States and Canada.Bryologist 98: 467–549.

Fryday, A. M. (1991) A microscopic test for confluenticacid. British Lichen Society Bulletin 70: 31.

Fryday, A. M. (1996a) The lichen vegetation of somepreviously overlooked high-level habitats in NorthWales. Lichenologist 28: 521–541.

Fryday, A. M. (1996b) Porpidia zeoroides (Anzi) Knoph& Hertel. In New, Rare and Interesting British Lichenand Lichenicolous Fungus Records (C. B. J. Hitch,ed.). British Lichen Society Bulletin 78: 62.

Fryday, A. M. (1997a) Ecology and Taxonomy ofMontane Lichen Vegetation in the British Isles. Ph.D.Thesis, University of Sheffield.

Fryday, A. M. (1997b) Montane lichens in Scotland.Botanical Journal of Scotland 49: 367–374.

Fryday, A. M. (2001a) The lichen vegetation associatedwith areas of late snow-lie in the Scottish High-lands. Lichenologist 33: 121–150.

Fryday, A. M. (2001b) Phytosociology of terricolouslichen vegetation in the Cairngorm mountains,Scotland. Lichenologist 33: 331–351.

Fryday, A. M. (2002a) Distribution and importance ofthe lichen vegetation of the Scottish Highlands.Botanical Journal of Scotland 54: 133–151.

Fryday, A. M. (2002b) A revision of the species of theRhizocarpon hochstetteri group occurring in theBritish Isles. Lichenologist 34: 451–477.

Fryday, A. M. (2005) Proposal to reject the nameLecidea flavo-coerulescens Hornem. (lichenizedAscomycete, Porpidiaceae) Taxon (in press).

Fryday, A. M. & Coppins, B. J. (1997) Keys tosterile crustose saxicolous and terricolous lichensoccurring in the British Isles. Lichenologist 29:301–332.

Fryday, A. M., Fair, J. B., Googe, M. S., Johnson, A. J.,Bunting, E. A. & Prather, L. A. (2001) Checklist oflichens and allied fungi from Michigan. Contribu-tions from the University of Michigan Herbarium 23:145–223.

Galloway, D. J. & Coppins, B. J. (1992) PorpidiaKörber (1885). In The Lichen Flora of Great Britainand Ireland (O. W. Purvis, B. J. Coppins, D. L.Hawksworth, P. W. James & D. M. Moore, eds):494–499. London: Natural History MuseumPublications.

Gilbert, O. L. & Coppins, B. J. (1992) The lichens ofCaenlochan, Angus. Lichenologist 24: 143–163.

Gilbert, O. L & Fox, B. W (1985). Lichens of highground in the Cairngorm mountains, Scotland.Lichenologist 17: 51–66.

Gilbert, O. L. & Fox, B. W. (1986) A comparativestudy of the lichens occurring on the geologicallydistinctive mountains of Ben Loyal, Ben Hope andFoinaven. Lichenologist 18: 79–93.

Gilbert, O. L. & Fryday, A. M. (1996) Observations onthe lichen flora of high ground in the West ofIreland. Lichenologist 28: 113–127.

Gilbert, O. L. & Giavarini, V. J. (1993) The lichens ofhigh ground in the English Lake District. Lichenolo-gist 25: 147–164.

Gilbert, O. L., Fox, B. W. & Purvis, O. W. (1982) Thelichen flora of a high-level limestone-epidioriteoutcrop in the Ben Alder range, Scotland.Lichenologist 14: 165–174.

Gilbert, O. L., Coppins, B. J. & Fox, B. W. (1988) Thelichen flora of Ben Lawers. Lichenologist 20: 201–243.


Gilbert, O. L., Fryday, A. M., Giavarini, V. J. &Coppins, B. J. (1992) The lichen vegetation ofhigh ground in the Ben Nevis range, Scotland.Lichenologist 24: 43–56.

Gowan, S. P. (1989a) The lichen genus Porpidia (Por-pidiaceae) in North America. Bryologist 92: 25–59.

Gowan, S. P. (1989b) A character analysis of thesecondary products of the Porpidiaceae (lichenizedAscomycotina). Systematic Botany 14: 77–90.

Gowan, S. P. & Ahti, T. (1993) Status of the lichengenus Porpidia in Eastern Fennoscandia. AnnalesBotanici Fennici 30: 53–75.

Greuter, W., McNeill, J., Barrie, F. R., Burdet, H. M.,Chaloner, W. G., Demoulin, V., Filgueiras, D. H.,Nicolson, D. H., Silva, P. C., Skog, J. E., Trehane,P., Turland, N. J. & Hawksworth, D. L. (eds)(1994) International Code of Botanical Nomenclature(Saint Louis Code). Regnum Vegetabile, 138.Konigstein: Koeltz Scientific Books (for the Inter-national Association for Plant Taxonomy).

Harris, R. C. (1977) Lichens of the Straits Counties,Michigan. Published by the author.

Hawksworth, D. L., James, P. W. & Coppins, B. J.(1980) Checklist of British lichen-forming, licheni-colous and allied fungi. Lichenologist 12: 1–115.

Hertel, H. (1975) Beiträge zur Kenntnis der Flechten-familie Lecidieaceae VI. Herzogia 3: 365–406.

Hertel, H. (1977) Gesteinsbewohnende Arten der Sam-melgattung Lecidea (Lichenes) aus Zentral-, Ost-und Südasien. Khumbu Himal, Ergebnisse des Forsc-hungsunternehmens Nepal Himalaya 6: 145–378.

Hertel, H. (1984) U} ber saxicole, lecideoide Flechtender Subantarktis. Beiheft zur Nova Hedwigia 79:399–499.

Hertel, H. & Knoph, J.-G. (1984) Porpidia albocaerules-cens eine weit verbreitete, doch in Europa selteneund vielfach verkannte Krustenflechte. Mitteilun-gen der Botanischen Staatssammlung München 20:467–488.

Inoue, M. (1983) Japanese species of Huilia (Lichenes)(1–3). Journal of Japanese Botany 58: 113–128,161–173, 225–236.

Körber, G. W. (1855) Systema Lichenum Germaniae.Breslau: Trewendt & Granier.

Körber, G. W. (1865) Parerga Lichenologica. Breslau:Eduard Trewendt.

Knoph, J. G. (1984) Vorarbeiten zu eine Monographieder euthallinen Arten der Flechtengattung Porpidia(Porpidiaceae, Lecanorales) Europas, mit besondererBerücksichtigung des Alpengebietes. Institut fürSystematische Botanik der Universität München.

Lynge, B. (1939) Lichens from Jan Mayen collected onNorwegian expeditions in 1929 and 1930. Skrifterom Svalbard og Ishavet 76: 1–56.

Magnusson, A. H. (1952a) Lichens from Torne Lapp-mark. Arkiv för Botanik, series 2 2: 45–249.

Magnusson, A. H. (1952b) Key to the species of Lecideain Scandinavia and Finland. Svensk BotaniskTidskrift 46: 178–198.

Meyer, B. & Printzen, C. (2000) Proposal for a stand-ardized nomenclature and characterization of in-soluble lichen pigments. Lichenologist 32: 571–583.

Purvis, O. W., Coppins, B. J. & James, P. W. (1993)Checklist of lichens of Great Britain and Ireland.British Lichen Society Bulletin 72 (supplement):1–75.

Rambold, G. (1989) A monograph of the saxicolouslecideoid lichens of Australia (excl. Tasmania).Bibliotheca Lichenologica 34: 1–345.

Sánchez-Biezma, M. J. & López de Silanes, M. E.(1999) Porpidia nadvornikiana, a species of ultra-basic rocks: second record for Europe. Lichenologist31: 637–639.

Santesson, R. (1993) The Lichens and LichenicolousFungi of Sweden and Norway. Lund: SBT-förlaget.

Schwab, A. J. (1986) Rostfärbene Arten der Sammel-gattung Lecidea (Lecanorales) Revision der ArtenMittel-und Nordeuropas. Mitteilungen der Bota-nischen Staatssammlung München 22: 221–476.

Stearn, W. T. (1992) Botanical Latin. Newton Abbot:David & Charles.

Taylor, T. (1836) Lichens. In Flora Hibernica (J. T.Mackay, ed.): 71–165, 257–260. Dublin: W.Curry:

Vainio, E. A. (1934) Lichenographia fennica IV. Leci-deales II. Acta Societatis pro Fauna et Flora Fennica.57: 1–531.

White, F. J. & James, P. W. (1985) A new guide tomicrochemical techniques for the identificationof lichen substances. British Lichen Society Bulletin57 (supplement): 1–41.

Wirth, V. (1980) Flechtenflora. Stuttgart: Verlag EugenUlmer.

Accepted for publication 1 October 2004


the genus porpidia in northern and western europe,...

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