MagnoliaThe Journal of the Magnolia Society International

Volume 46 Issue No. 90 Fall/Winter 2011

EditorCheryl Doyle Kearns102 Colonial Drive

Youngsville, NC 27596919.556.6429

cherylkea1017@yahoo.com

Page Layout and DesignAaron Schetttler

Raleigh, NCschettleraaron@gmail.com

Scientific AdvisorRichard B. Figlar

Pickens, SC magnolia@magnoliaceae.org

Contents2011 Gresham Awards presented ........................................................................ 1The Magnolia collection at the JC Raulston Arboretum at NC State University ................. 4Asiatic Magnolias and the UBC Botanical Garden ................................................... 8A comprehensive evaluation of yellow-flowering Magnolias ...................................... 13Ploidy level, genome size, and the music of Magnolias .......................................... 30Exploring in Vietnam ......................................................................................... 52New cultivar registrations 2010-2011. ................................................................ 58

Front Cover: Pink-flowered form of M. delavayi, JC Raulston Arboretum (photo by Mark Weathington)Back cover: Vance Hooper's award-winning M. 'Genie' (M. 'Sweet Simplicity' x M. liliiflora 'Nigra') x (M. 'Sweet Simplicity' x M. 'Black Tulip') (photo by Vance Hooper)

Inside: All photographs by respective authors unless otherwise noted.

MAGNOLIA, Journal of the Magnolia Society International (ISSN 0738-3053) is published two times a year by the Magnolia Society International, Inc., a not-for-profit society, as a service to its members. Address inquiries about membership and requests for copies of the bylaws to the secretary: Beth Edward, 3000 Henneberry Road, Jamesville, NY 13078, USA.

Dues payments, orders for back issues of this journal, payment or inquiries concerning advertisements, and orders for publications should be addressed to the treasurer: Larry Langford, 518 Parker Street, Gibson, TN 38338, USA.

Editorial contributions and inquiries about publishing articles and requirements for manuscripts, art work, or photographs for publication should be addressed to the editor.

Visit the Web site: www.magnoliasociety.org

Magnoliathe Journal of the Magnolia Society International

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2011 Gresham Awards presentedThe D. Todd Gresham Award was established in 1981 in order to recognize individuals who have made extraordinary contributions to the develop-ment, improved culture, increased knowledge and promotion of magno-lias, or who have contributed outstanding service to the Magnolia Society.

Lola Koerting was honored at the Magnolia Society’s banquet dinner on May 7 and Steve Spongberg was honored on May 10 during a separate ceremony which took place at the Stephen A. Spongberg Library at Polly Hill Arboretum. Dick Figlar, Awards and Honors Chairman, made the following presentations at those ceremonies.

Lola KoertingThe story of tonight’s award recipient begins at the 1977 annual meeting of Magnolia Society at Washington, DC. I was at that meeting (it was my first) as were a few others here tonight, inc luding Gordon Hagen, Elliott Jessen and Harry Heineman. During the Friday night presentations, a young and enthusiastic Plant Researcher from Brooklyn Botanic Garden (BBG) took to the podium with a slide carousel and proceeded to show to the Magnolia Society – and the horticulture world – something that had never been seen before: slide after slide of yellow-flowered precocious magnolias – the first ever hybrids between M. acuminata and M. denudata. The entire audience was astonished, energized and everything in between. Even the normally demure Joe McDaniel later referred to these photographs as “an arresting sight” in his write-up of the meeting.

By now, you all know we are talking about Lola Koerting.

During that time and in the years that followed, Lola went on to energize and invigorate the magnolia breeding program at the BBG’s Kitchawan Research station near Ossining, NY. Not only an accomplished plant sci-entist and magnolia breeder herself, Lola’s sheer enthusiasm and passion for her work served as a catalyst for action within a bureaucratic - some-times slow-moving - BBG organization. Thus, largely as a result of her ef-

Awards Committee Chairman Dick Figlar (L) and MSI President Andrew Bunting (R) with Gresham Award recipient Lola Koerting. (photo by Anita Figlar)

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forts, at least six important magnolias were introduced: ‘Elizabeth’ (1977), ‘Yellow Bird’ (1981), ‘Hattie Carthan’ (1984), ‘Marillyn’ (1989), ‘Lois’ (1998), and ‘Judy Zuk’ (2007).

More importantly, Lola’s influence on magnolia breeding went far beyond the BBG. That the notoriously “non-showy flowered” M. acuminata could successfully be used to extend the hardiness and color ranges of exist-ing showy magnolias represented a major paradigm shift in magnolia de-velopment. Contemporary magnolia breeders of that time, Joe McDaniel, Phil Savage, David Leach and others, quickly began incorporating Mag-nolia acuminata into their own breeding programs. Later, August Kehr, Frank Galyon, Dennis Ledvina and others would use those early hybrids as parents in more complex crosses, resulting in second generation hy-brids like ‘Daybreak’ (from M. ×brooklynensis and a Gresham hybrid), and

‘Blushing Belle’ (from ‘Yellowbird’ and ‘Caerhays Belle’). As a result of all this, during a time when public interest in other woody plants was declining, interest in magnolias and the Magnolia Society was expanding

– worldwide.

Dr. Craig Hibben, one of Lola’s former supervisors at BBG, mentioned to me recently that along with all of her success, “some of the bureaucracy at the BBG still didn’t know what a jewel they had.” Well, we do, Lola! Tonight, it is with great pleasure we honor you with the D. Todd Gresham Award. Congratulations and thank you, Lola Koerting.

Stephen A. SpongbergStephen A. Spongberg received his Ph.D. in Botany from the University of North Carolina at Chapel Hill. In 1970 he began his 28-year tenure at the Arnold Arboretum of Harvard University, first as Assistant Cura-tor, later as Horticultural Taxonomist as well as Editor of the prestigious Journal of the Arnold Arboretum for its final 12 years of its regular publi-cation. It was here where he authored a series of modern treatments of cultivated woody plants. Among these were Lauraceae Hardy in Temperate North America, Styracaceae Hardy in Temperate North America and, of course, Magnoliaceae Hardy in Temperate North America. This 1976 monographic account of the temperate Magnolias was the first detailed and comprehen-sive treatment since G.H. Johnstone’s 1955 Asiatic Magnolias in Cultiva-tion and J.G. Millais’ Magnolias in 1927. While it superseded Johnstone in scope, it replaced the largely obsolete Millais volume in its accounts of the temperate magnolias. More importantly, Steve’s work quickly inspired others – most notably Neil Treseder (1978) , Dorothy Callaway (1994), Jim Gardiner (1989, 2000) - to build and expand upon what he had started, thus ushering in a prosperity of Magnoliaceae knowledge that had been unimaginable before 1976. Over the past 35 years, Magnoliaceae Hardy in Temperate North America has consistently been one of the most frequently cited references in both popular and scientific Magnoliaceae literature.

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Of course, Steve’s work went far beyond Magnoliaceae. In 1980 he partici-pated in the Sino-American Botanical Expedition to western Hubei Prov-ince in The People’s Republic of China. This historic trip was the first-ever cooperative venture between Chinese and American scientists. In 1990 he authored A Reunion of Trees - a comprehensive history of the global ex-ploration for woody plants. This highly regarded account is listed by the American Horticulture Society as one of the seventy-five greatest garden books published in the 20th century. In 1996 he was awarded the pres-tigious Gold Veitch Memorial Medal by the Royal Horticultural Society. After his tenure at the Arnold Arboretum in 1998, he became the first di-rector of the Polly Hill Arboretum on Martha’s Vineyard and served six years. Polly Hill said, “When Steve accepted the job, way back when, I felt so lucky I could hardly believe it - he has fulfilled those dreams con-sistently and beautifully.”

Steve continues a vital role at the Arboretum as an honorary board mem-ber and Director Emeritus. In 2010, the Stephen A. Spongberg Library was established in his honor.

On behalf of the Magnolia Society International, it gives us great pleasure to present the D. Todd Gresham Award to Steve Spongberg.

(L to R) Dick Figlar, Steve Spongberg and Andrew Bunting after ceremony awarding Spongberg with the Gresham Award. They are standing in front of the Polly Hill Arboretum library recently named to honor Spongberg. (photo by Tom Clark)

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The Magnolia collection at the JC Raulston Arboretum at NC State UniversityMark Weathington, Assistant Director and Curator of Collections, JC Raulston Arboretum at NC State University, Raleigh, NC

The JC Raulston ArboretumThe JC Raulston Arboretum (JCRA) is a nationally acclaimed garden with one of the most diverse collections of cold-hardy temperate zone plants in the southeastern United States. As a part of the Department of Horticul-tural Science at NC State University in Raleigh, NC, the JCRA is primarily a research and teaching garden that focuses on the evaluation, selection and display of plant material gathered from around the world and plant-ed in landscape settings. Plants especially adapted to Piedmont North Carolina conditions are identified in an effort to increase the diversity in southern landscapes. The JCRA’s 10 acres and nursery contains over 8300 accessions of over 5000 different taxa.

The JCRA’s location in the central piedmont of North Carolina allows us to grow a wide diversity of plant material. Our temperatures generally range from about -12°C (10°F) to 35°C (95°F), but temperatures much low-er and higher are not unknown. The average annual precipitation mea-sures 109cm (43 in) and in most months the area receives about 7.5-10cm (3-4in).

The Magnolia collectionMagnolias have been an important part of the collections of the JCRA from its inception and we are currently applying to be part of the multi-institution North American Plant Collections Consortium Magnolia collec-tion. The first accessioned magnolia dates to 1977, less than a year after the arboretum founder and namesake, J.C. Raulston, arrived at NC State University. This Magnolia ×loebneri ‘Merrill’ still graces the Klein-Pringle White Garden where it welcomes the spring with a glorious floral display.

The JCRA’s Magnolia collection represents a broad diversity of both spe-cies and cultivars comprised of 133 different taxa, including 32 species. We currently hold accessions from 8 of the 12 sections of the genus Mag-nolia, lacking only taxa in the mostly tropical Talauma, Kmeria, and Man-glietiastrum sections and our own North Carolina native Auriculata section. We have a particular focus on members of section Michelia, with 19 taxa in this group alone. The complete list of magnolias planted on the grounds of the JCRA can be found on our website (www.ncsu.edu/jcraulstonarbo-retum) under the “Current Plantings” heading in the “Horticulture” tab. Photographs of many of our magnolias can also be found on the website in the “Photography” section.

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The evergreen plants in section Michelia are especially valuable since they provide structure, and often flowers, during our relatively mild winters. Magnolia ernestii has made a handsome, narrowly upright evergreen tree in the southwest corner of the Japanese Garden where it now towers over the 8ft wall. The glossy green leaves are quite attractive and the flowers, although not terribly showy, are delightfully fragrant when they appear in late winter to early spring. Our plants (another grows in the Winter Garden) were acquired in 1995 and 1997 and have grown to nearly 20ft in that time. Another choice plant in this section rising above the lath house is M. cavaleriei, which begins flowering in December and contin-ues to March. The large, loose white flowers often exhibit winter dam-age, but can be stunning against the clear blue winter sky. Another sec-tion member that hasn’t yet made it out of the nursery is M. compressa, which I collected in Taiwan in 2009. These seedlings come from plants growing at over 2100m (7000ft) in central Taiwan and should prove to be hardy. In the wild these trees had straight, smooth trunks and were identifiable mainly by the oc-casional fruit found among the leaf litter on the ground. We hope to be able to distribute this collection in the not too distant future if it proves to be garden-worthy.

M. lotungensis in section Gynopodium has been happily growing in our lath house since 1998 and finally consented to flower a decade later. The creamy cup-shaped flowers are quite lovely in April and May, but can be

difficult to see since they are gener-ally above the roof of the structure. It forms a very distinctive upright, narrow pyramid with new foliage often tinted red when it first emerg-es in the spring. I am told it is used as a street tree in Yunnan where it is native and I have seen it growing in gardens in Hangzhou. Nearby in our new Asian Valley from section Gwillimia is a very attractive pink-flowered form of M. delavayi. The large foliage has suffered some win-

ter damage, but has still flowered well. We will be watching this form closely to see if it proves to be reliably hardy with age.

Magnolia lotungensis

Magnolia cavaleriei

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Another mostly ever-green section, Man-glietia, is home to M. fordiana, a lovely nar-row-leafed tree with cupped white flowers. Our plants are still rela-tively young, but I get to enjoy the related and similar M. yuyuanensis as a hedge outside my office in full flower as I write this article in late April. Both make beautiful specimens, but can be painfully slow to flower and difficult to propagate. Our hedge was planted with the intention of coppicing in the hopes that the young vigorous shoots would root more readily, but to date we have balked at the seeming sacrilege when confronting them with the pruning saw.

The JCRA, of course, also has significant collections of deciduous magno-lias in section Yulania, with a multitude of plants ranging from M. amoena to M. zenii. We love the delicate pink to white flowers deepening to bur-gundy at the base of the tepals in both species and the purplish anthers of the former species, which are reddish in the latter. The large flowers on bare early spring branches of this section are highlights of the eastern end of the Arboretum, where the bulk of the magnolia collection is situated.

While we hold significant collections of species magnolias, cultivars also are well represented at the JCRA. Magnolia ‘Coral Lake’ is a particular fa-vorite of visitors because of its very late, large, double pink flowers high-lighted with streaks of yellow. It has been thriving at the head of our Scree

Garden where its April flowers and upright habit form a colorful sentry. An older se-lection, but still one of my personal favorites, is M. stellata ‘Chrysan-themiflora’. The clear pink color of the mul-titude of tepals (36-40) on a small-statured tree are unmistakable and, in my mind, are

Magnolia fordiana (photo by A. Schettler)

Magnolia 'Coral Lake' (photo by A. Schettler)

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unsurpassed by any other pink star magnolia. In a nod of appreciation to the diversity of our own native evergreen magnolias, the collection holds 11 taxa of M. virginiana and 18 of M. grandiflora. The small-leaved selections of M. virginiana ‘Perdido’ and M. v. ‘Coosa’ add an unusual texture to the magnolia collection and should be more widely grown, especially in smaller gardens. The white flowers of both are medium-sized but appear relatively large against the undersized leaves and have the clean, lemony fragrance typical of the species.

Increasing awareness The JC Raulston Arboretum has always endeavored to increase the di-versity of the American landscape through evaluation of plant material, display of novel and superior selections, and dissemination of knowledge and plants. Over the last 15 years, the JCRA has distributed thousands of plants to nurserymen, other gardens, and Arboretum members. Among these allotments have been magnolia distributions in larger numbers, in-cluding M. sieboldii, M. figo ‘Port Wine’, M. zenii, M. yuyuanensis, M. chap-ensis, M. laevifolia ‘Michelle’, M. denudata ‘Forrest’s Pink’, and M. insignis, among many others. Hopefully, this results in creating more magnolia enthusiasts in the process.

We are in the process of evaluating our collection, making systematic re-movals of plants which no longer fit into our collection priorities and ag-gressively adding new forms. Our dynamic collection keeps the JCRA fresh and ensures that there is always something new to see on each visit. After all, life is too short for boring plants.

Magnolia virginiana var. australis 'Coosa'

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Asiatic Magnolias and the UBC Botanical GardenAndy Hill, Curator-Horticulturist, David C. Lam Asian GardenUBC Botanical Garden and Centre for Plant Research, Vancouver, BC

The University of British Columbia (UBC) Botanical Garden has a fine his-tory of Magnolia study that goes back a half century to the early plantings in the David C. Lam Asian Garden. The 10-hectare (25-acre) garden was originally being developed as a collection of rhododendrons by then Cu-rator Peter Wharton who soon expanded that early vision to include other associated woody plants. Principal among those were the much-loved magnolias, many of which were uncommon, with new species still to be discovered and added to the Garden.

Early plantings in the UBC Asian Garden were of section Yulania and included favorite cultivars such as M. dawsoniana ‘Chyverton’, M. sprengeri ‘Claret Cup’, M. s. ‘Copeland Court’, M. s. ‘Wakehu-rst’, M. campbellii subsp. campbellii ‘Ethel Hillier’ and M. c. subsp. mol-licomata ‘Lanarth’. As the goals of research and conservation grew in importance, so did the preference for wild-collected species with known provenance. Valuable seed began to arrive at the Garden through a wide network of magnolia friends and the var-ied species began to dominate the collections. The Garden’s own expedi-tions into wild places across Asia were also contributing to the community, with fieldwork carried out in South Korea, China and northern Vietnam.

Fieldwork and researchPerhaps one of the most important of these expeditions was the work done in 2006 on Magnolia sargentiana. Along with Dr. Ya Tang and colleagues from Sichuan University, Peter Wharton was part of a group that was able to locate new ranges of this red-listed species in the Meigu Dafengding Nature Reserve. This helped the Chinese government, which had already established sensitive regions and plant groups, to set up new protection areas and further conservation efforts. Seed was collected and distributed internationally to various botanic gardens and scientific institutions for

Peter Wharton with Magnolia 'Eric Savill' at UBC Botanical Garden

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ex situ study, with a number of specimens added to the UBC Botanical Garden.

Fieldwork in Asia has continued with recent ex-peditions to Sichuan Province, in western China. Two trips in 2010 with Quarryhill Botanic Gar-den, Sichuan University, Shenzhen Botanic Gar-den and Ya’an Botanic Garden sought to collect a range of data and locations of magnolia spe-cies in bloom early in the year, then return to col-lect seed and supplemental data in the autumn. These expeditions have been successful, with a large number of M. wilsonii, M. sargentiana and M. dawsoniana examined and specimens col-lected. The geotagged data will be compiled in a new spatial database we are developing to assist in future fieldwork. All of this, hopefully, will add a little more to our collective knowledge of the amazing genus.

The UBC Botanical Garden is committed to the study of Magnolias, both in their native ranges and within our own collections. One project that is just now passing twenty years of activity is the continuing Magnolia Phe-nology Study. A passionate group of volunteers have recorded observa-tions relating to bloom times—information that will be compared against weather data for that period and examined for trends. We have noticed significant variation in data from year-to-year observations and will soon be able to see exactly what changes have occurred.

Evergreens at the UBC Botanic Garden Vancouver is fortunate to have a mostly gentle climate. The Asian Gar-den is in a particularly sheltered spot below a towering canopy of na-tive conifers (Pseudotsuga menziesii, Abies grandis, Thuja plicata and Tsuga heterophylla), and influenced by the Pacific Ocean, which is close by. The temperature rarely drops below -10C/14F. On average, 125cm (50in) of rainfall is measured annually; however, most of that arrives in the winter, making it necessary to irrigate through the summer. We can grow a sur-prising range of plants and it was an inspired decision early on to begin experimenting with the evergreen magnolias.

In an article that appeared in the UBC Botanical Garden Journal, Davidso-nia, in 2006, Peter Wharton provided an update on how these evergreen species were performing in Vancouver. At that time he wrote, “A major challenge for many species is sudden cold, often with heavy wet snow, a common winter event in the Pacific Northwest. Branch and crown form, strength of branch and stem attachments, branch flexibility, and the snow

Author and guide next to Magnolia dawsoniana

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shedding attributes of leaves are all factors that influence survival and attractiveness under this threat.” This observation proved prescient, espe-cially during this past winter where foul weather arrived unusually early in November (down to nearly -7C (20F), strong winds and heavy wet snow and returned again, nearly as dramatically, at the end of February.

In the five years since that report we have lost a few promising species, including M. doltsopa (section Michelia) and M. floribunda (section Michelia). A few others in very poor condition are scheduled for removal. But there have also been some real stars.

Here is a brief update of the Asiatic evergreen species magnolias at the UBC Botanical Garden in 2011.

Magnolia aromatica (section Manglietia) - One weak plant, poorly sited with too much shade and drought. Minimal growth, but leaves and buds look little damaged. Not a fine specimen. We are propagating it and expect bet-ter luck in another part of the Garden.

Magnolia cavaleriei var. platypetala (section Michelia) - Perhaps 90% defoli-ated from the winter and some broken branches. Not at all happy with the harsh weather of early November.

Magnolia chevalieri (section Manglietia) - One of our worst for frost burn and marked leaves, though, if past experience is true, it should recover well through the summer.

Magnolia conifera (section Manglietia) - A fantastic tree. Most promising and perfectly content, even after the last winter. Strong, even branching, no breaks...even with minimal protection. Leaves and buds seem almost completely unblemished. We’re very excited about this species and it ap-pears it may bloom well this year.

Magnolia sprengeri after an ice storm April 13, 2010

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Magnolia ernestii (section Michelia) - Another great performer, at least in its sheltered position below our native conifers. Some broken branches but little frost damage to the foliage, though somewhat difficult to tell as it’s now approaching 10m (33ft) in height with a high crown.

Magnolia fordiana var. fordiana (section Manglietia) - There are a number of trees and most have looked quite bad for many years. Very spindly growth, yellowed leaves and repeated damage from cold and snow. Pos-sibly improved fertility would help, as well as a less exposed site (our best tree is growing in half shade and our worst, totally open).

Magnolia foveolata (section Michelia) - Despite being well protected by the over-story of larger conifers, this tree suffered some significant branch damage from snow loading, including the top 2-3m (10ft) of its central leader. This is truly a shame, because the large glossy leaves and new buds appear mostly to have made it through the cold without too much injury. This was one of Peter Whar-ton’s favorites and he would argue it has great potential for this region.

Magnolia insignis (section Manglietia) - Looks absolutely perfect, as usual. Leaves unmarked and lots of healthy flower buds. This tree receives a fair amount of indirect light and some shelter from nearby conifers that deflect the worst of the winter weather.

Magnolia lotungensis (section Gynopodium) - A really lovely tree, surpris-ingly undamaged by the heavy snows or the cold temperatures. Definitely another one to watch.

Magnolia martini (section Michelia) - Two trees -- one terrible and the other just very bad. Many broken branches (over half of the one tree) and both with yellowed and burned leaves, buds and wood. It’s becoming difficult to justify their continued place in our collection.

Magnolia maudiae (section Michelia) - Possibly our best of the recent mag-nolia additions. Unscathed with very strong growth. We have three trees, all Peter Wharton collections and all with some shelter and moist (though not necessarily well-drained) sites. They look terrific.

Magnolia foveolata at UBC Botanical Garden (Photo by Douglas Justice)

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Magnolia nitida (section Gynopodium) - This young tree is a bit of a surprise for us. It was rediscovered in an overgrown, shady and dry corner of the Garden (during some plant exploration in our own garden!) then some-what brutally transplanted early last season. In the last year it has grown nearly 0.5m (2ft) and is now approx. 2.5m (8.5ft) tall, and is completely at home. The small, glossy leaves and tiny buds are perfect.

Magnolia yunnanensis (section Gynopodium) - This tree is located beside our M. aromatica and suffers the same conditions of dry, poor soil and competition from neighboring plants, of which it is not at all tolerant. It was nearly totally defoliated from this winter and is in serious decline. We are in the process of propagating this tree and hopeful that it will do better elsewhere in the Garden.

Looking aheadIn the coming year, UBC Botanical Garden will participate in a multi-site North American Plant Collections Consortium registration of the genus Magnolia. This will help articulate our commitment to magnolias and firmly place the group as a priority taxon in our policies and planning. The Garden’s position within the University’s organizational structure has changed and we are now part of the new UBC Biodiversity Collections group in the Faculty of Science. This brings increased access to UBC re-searchers and resources, as well as the outstanding UBC Herbarium. It is our intention to continue to play a lead role in both in situ and ex situ conservation, research and education while developing a beautiful gar-den (and this genus really does make it so easy) that will delight visitors.

ReferencesWANG, J., TANG, Y., XIE, Z.-H. and ZHANG, M.-Y. (2009), Autecology and conservation status of Magnolia sargentiana Rehder & Wilson (Mag-noliaceae) in the Dafengding region, southern Sichuan Province, China. Journal of Systematics and Evolution, 47: 525–534. doi: 10.1111/j.1759-6831.2009.00051.x.

WHARTON, A.P. (2006). Evergreen Magnolias Growing at UBC Botanical Garden, Vancouver, Canada: a Progress Report. Davidsonia 17(4):116-133.

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A comprehensive evaluation of yellow-flowering MagnoliasDonna C. Fare, Research Horticulturist, USDA-ARS, US National Arboretum

IntroductionDeciduous magnolias are well adapted to many landscape situations and are highly desirable due to their floriferous nature. About 800,000 flower-ing magnolias are sold each year in the US and about 10% of the nurseries that grow them are located in Tennessee (USDA, 2010). Yellow-flowering deciduous magnolias are becoming popular landscape plants because they offer an unusual color palette (Knox, 2002). There are very few yel-low-flowering small trees in the landscape plant inventory.

This research project was conducted at the Tennessee State University (TSU) Nursery Research Center located in the heart of the nursery indus-try in Tennessee on the border of USDA Hardiness Zones 6 & 7. The area is known as a climatic and geographic transition zone. Plants raised in this area can be used in landscapes in as far north as Zone 5 and as far south as Zone 8. Plant evaluations made in transition zones are ideal be-cause results can be utilized over a wide geographic and climatic area.

The primary objective of this research project was to compare yellow-flowering magnolias for flower color intensity, flower size and duration, as well as growth rate and canopy form. A secondary goal was to develop a performance record of magnolias planted in a replicated trial in one lo-cation to assist plant breeders for future plant development.

Materials and MethodsMany selections of yellow-flowering magnolias are only available in low numbers and small sizes. For this project, plants were purchased, grown in a #3 or #5 container for a year, and planted in the evaluation plot the following spring. Magnolias were first planted in March 2006 in a field plot with 4.6 m (15 ft) in-row spacing and 3.7 m (12 ft) between rows in a well-drained silt loam soil (Waynesboro). Each magnolia selection was planted in a randomized block design with three single plant replications. Plants were maintained with traditional management, including fertil-ization, mulching and weed control. Pruning was limited to removing branches from the trunk about 61 cm (24 in) above the soil line. Irriga-tion was applied during the growing season in periods of drought. In March 2007, unseasonably warm temperatures occurred. Many plants had broken dormancy and were leafing out. Within a couple of weeks in early April 2007, a hard freeze occurred, lasting for several days. Many of the magnolia selections were killed or suffered severe dieback. Plantings were reestablished. Currently, we have 37 selections of yellow-flowering magnolias under evaluation (Magnolia Society, 2010). Due to the differ-

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ent planting dates (Table 1), growth data presented in Tables 1 and 2 were calculated by subtracting height and caliper measurements in the spring from fall measurements to determine growth during each year. In 2009 and 2010, 5 leaves were selected from each plant to determine leaf area (only data from 9 June 2010 shown). Flowering duration was determined from recording the first flower to the last flower when tepal color no lon-ger had a visual impact. On the first day that selected flowers opened, three were selected to determined tepal color using the Royal Horticultur-al Society color chart and a portable spectrophotometer (Minolta 2600d) (only data from April 6 and April 9, 2010 shown). All data was statistically analyzed using the general linear model in SAS 9.1. Mean separation was performed with Fisher’s protected LSD with alpha = 0.05.

Results and DiscussionIn 2007, plant growth was slow due to the effect of the April freeze. Dur-ing 2008 to 2010, Magnolia ‘Goldfinch’, M. ‘Gold Star’ and M. ‘Banana Split’ had the greatest average height growth of 114 cm, 99 cm and 97 cm, re-spectively (Table 1). The slowest growing selection was M. ‘Golden Sun’ with an average of 22 cm during 2009 to 2010. Slow growth appears to be typical for many of the yellow flowering magnolia selections during the first year or two after transplanting. Yearly height growth increased after the third year in the test with many selections.

SelectionY Date PlantedAnilouY 2010 - - - - -Banana Split 2009 - - - 109 a 85 bcdBlue OpalY 2010 - - - - -BrendaY 2010 - - - - -Butterflies 2006 97 aX 23 bcd 70 bcd 58 a-f 78 bcdCarlos 2009 - - - 69 a-f 115 abCoral LakeY 2009 - - - - -DaphneY 2010 - - - - -Daybreak 2007 - 2 d 18 cde 85 a-e 73 bcdElizabeth 2006 42 bc - 49 cd 7 g 74 bcdEvamaria 2009 - - - 76 a-f 86 bcdGold CupY 2010 - - - - -Gold Star 2006 100 a 47 abc 239 a 31 efg 80 bcdGolden Gala 2009 - - - 70 a-f 90 bcdGolden Gift 2007 - 107 a 35 e 31 efg 24 eGolden PondY 2010 - - - - -Golden RainY 2010 - - - - -Golden Sun 2009 - - - 47 c-f 65 cdeGoldfinch 2008 - - 85 bc 109 a 148 a

Height growth, cmZ

2007 2008 2009 20102006

Table 1. Date planted and height growth of selected yellow-flowering Magnolia selections in McMinnville, Tenn from 2006 - 2010.

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Trunk diameters were measured 30 cm (12 in) above the soil surface. Trunk growth averaged from 9 mm to 29 mm during the test (Table 2). M. ‘Carlos’, M. ‘Yellow Lantern’, M. ‘Sundance’, M. ‘Gold Star’ and M. ‘Gold-en Gala’ had the most trunk diameter increase and averaged over 25 mm (1 in) growth per year. M. ‘Golden Gift’, M. ‘Daybreak’, M. ‘Golden Sun’ and M. ‘Solar Flair’ had the least trunk diameter growth increase with yearly averages of 9 mm, 11 mm, 12 mm and 14 mm, respectively. Other selections had an intermediate increase in trunk diameter.

Canopy growth was calculated from an average of 2 canopy widths mea-sured from one drip line perpendicular to another in 2008, 2009 and 2010 (Table 2).

Table 1. Cont. SelectionY Date PlantedGreen BeeY 2010 - - - - -Honey LizY 2010 - - - - -Illini GoldY 2010 - - - - -Illini MoonlightY 2008 - - - - -Judy Zuk 2008 - - - 78 a-f 95 bcdKoban DoriY 2010 - - - - -Lois 2007 - 49 ab 53 cd 56 b-f 74 bcdMiss Honeybee 2008 - 2 d 86 bc 91 a-d 69 cdePetit ChiconY 2010 - - - - -Skyland’s BestY 2010 - - - - -Solar Flair 2006 30 bc 24 bcd 49 cd 74 a-f 70 bcdStellar Acclaim 2007 - 45 abc 53 cd 68 a-f 103 abcSun Ray 2006 38 bc 2 d 77 bcd 52 c-f 74 bcdSun Spire 2007 - 5 bcd 39 cde 71 a-f 72 bcdSunburst 2006 79 ab 22 bd 60 bcd 27 fg 66 deSundance 2006 55 ab 19 bcd 83 bc 63 a-f 78 bcdSunsation 2006 - 23 bcd 65 bcd 82 a-e 51 deYellow Bird 2008 - - 133 b 61 a-f 68 cdeYellow Lantern 2009 - - - 104 abc 75 bcdLSD 50 2 75 54 6

Height growth, cmZ

2007 2008 2009 20102006

ZHeight growth in 2006 = measurements made in Dec 2006 - April 2006; 2007 height growth = measurements made in November 2007 - March 2007; 2008 height growth= measurements made in December 2008 - March 2008; 2009 height growth = measurements made in November 2009 - March 2009; 2010 height growth = measurements made in November 2010 - March 2010.

XTreatments followed by the same letter are not significantly different. Means separated using Fisher's protected LSD, α ≤ 0.05.

YSelections have been planted in the evaluation, but have not been planted long enough to report results.

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SelectionBanana Split - - 19 ab 19 b 16 gh 34 ghi 72 fghButterflies 23 aY 27 bc 25 ab 20 b 158 a 155 ab 225 abCarlos - - 21 ab 30 ab 12 gh 54 e-i 128 d-hDaybreak - 2 e 14 ab 16 b 8 gh 25 i 62 hElizabeth 22 a 19 bcd 2 b 16 b 109 bcd 119 abc 149 cdeEvamaria - - 28 ab 10 b 14 gh 48 f-i 80 e-hGold Star 5 b 58 a 10 ab 37 ab 125 abc 163 a 231 aGolden Gala - - 28 ab 29 ab 29 fgh 70 c-i 160 a-dGolden Gift - 2 e 14 ab 10 b 53 efg 83 c-i 99 d-hGolden Sun - - 12 ab 12 b 17 gh 27 hi 68 ghGoldfinch - 6 de 29 ab 24 ab 21 gh 58 d-i 104 d-hJudy Zuk - - 15 ab 21 b 6 h 28 ghi 68 ghLois - 19 bcd 19 ab 21 b 75 def 113 a-d 147 c-fMiss Honeybee - 12 cde 30 a 24 ab 16 gh 64 c-i 110 d-hSolar Flair 14 ab - 19 ab 22 ab 83 cde 106 a-e 155 bcdStellar Acclaim - 13 cde 18 ab 21 b 51 e-h 78 c-i 143 c-gSun Ray 17 a 22 bcd 2 b 44 ab 143 ab 161 a 207 abcSun Spire - 13 cde 16 ab 17 b 13 gh 34 ghi 75 e-hSunburst 21 a 33 b 1 ab 11 b 104 bcd 103 b-e 142 c-gSundance 18 a 21 bcd 2 b 63 a 14 ab 162 a 209 abc

Canopy width, cmZ

2008 2009 2010Trunk caliper growth, mmZ

2007 2008 2009 2010

Sundance 18 a 21 bcd 2 b 63 a 14 ab 162 a 209 abcSunsation - 17 cde 22 ab 30 ab 25 gh 54 e-i 88 d-hYellow Bird 5 b 19 bcd 20 ab 16 b 48 e-h 85 c-g 122 d-hYellow Lantern - - 26 ab 26 ab 22 gh 52 e-i 119 d-hLSD 9 15 49 1 47 59 75

ZTrunk diameter growth was not meaured in 2006 and canopy width was not measured in 2006 and 2007; 2007 trunk diameter = measurements made in November 2007 - March 2007; 2008 trunk diameter and canopy width = measurements made in December 2008 - March 2008; 2009 trunk diameter and canopy width = measurements made in November 2009 - March 2009; 2010 trunk diameter and canopy width = measurements made in November 2010 - March 2010.

YTreatments followed by the same letter are not significantly different. Means separated using Fisher's protected LSD, α ≤ 0.05.

Table 2. Trunk diameter growth and canopy width of selected yellow-flowering Magnolia selections in McMinnville, Tenn from 2007 - 2010.

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By 2010, distinct canopy shapes were prominent with several cultivars. M. ‘Sun Ray’, M. ‘Gold Star’ and M. ‘Butterflies’ had the widest canopies among the selections and could be labeled as broadly ovate. These plants, along with M. ‘Solar Flair’, M. ‘Elizabeth’ and M. ‘Sundance’, were re-planted in 2007 after the freeze and had been evaluated for the longest period of time. M. ‘Sunburst’, M. ‘Sun Spire’ and M. ‘Golden Gala’ had the most upright growth habit and will probably become more distinct with age. Other selections in the evaluation have not been evaluated long enough to determine a distinct canopy form (Figure 1).

Butterflies Elizabeth

Golden Gala Lois

Figure 1. Canopy form of selected yellow-flowering Magnolias in McMinnville, Tenn. Images were taken in summer 2010.

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FoliageFoliage on the yellow-flowering magnolias were distinctly different among selections and a few with large leaves had an impact on the vis-ibility of the spring flowering. A CID leaf area meter, CI-203, was used to measure the surface area of leaves to determine the leaf size (Figure 2). M. ‘Carlos’, M. ‘Golden Gala’, M. ‘Sunsation’ and M. ‘Yellow Lantern’ had the

Sundance

Sunburst

Sun Ray

Solar Flair

Yellow BirdSun Spire

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largest leaves, which presented a coarse texture leaf form. In contrast, M. ‘Butterflies’, M. ‘Gold Star’, M. ‘Golden Gift’, M. ‘Miss Honeybee’ and M. ‘Sunburst’ had the smallest leaves.

Powdery MildewPowdery mildew (Erysiphe magnifica) has developed into a serious prob-lem in the evaluation (Figure 3). The percent of powdery mildew (PM) incidence on individual leaves and the percent of incidence on the total leaves per tree were rated during the summer months in 2008, 2009 and 2010 (only 16 Aug 2010 data shown in Table 3). All selections had some incidence of PM; however, by mid to late summer several selections had severe incidence. Greater than 40% of the leaf area of M. ‘Daybreak’, M. ‘ Evamaria’, M. ‘Golden Gala’, M. ‘Golden Sun’, M. ‘Solar Flair’, M. ‘Stellar Acclaim’, M. ‘Sunburst’, M. ‘Sunsation’ and M. ‘Yellow Bird’ had become affected by PM and over 60% of all the leaves on the plants had PM. Al-though only 15% of individual leaf surface of M. ‘Gold Star’ was affected with PM, every leaf on the tree had PM. M. ‘Sun Spire’ and M. ‘Carlos’ showed the least amount of PM on individual leaves and on the total leaves per tree. Two popular selections in the nursery trade, M. ‘Butter-flies’ and M. ‘Elizabeth’, had PM similar to M. ‘Sun Spire’ and M. ‘Carlos’. In Figure 4, the progression of PM during 2010 is shown with M. ‘Gold Star’, M. ‘Solar Flair’ and M. ‘Stellar Acclaim’. Near the end of the sum-mer, new foliage growth does not have the presence of PM, probably due to the unfavorable host environment.

Golden Gift

Golden Sun

Goldfinch

Judy Zuk

Lois

Miss Honeybee

Solar Flair

Stellar Acclaim

Sundance

Sun Ray

Sunburst

Sunsation

Sun Spire

Yellow Bird

Yellow Lantern

0 50 100 150 200 250

Banana Split

Butterflies

Carlos

Daybreak

Elizabeth

Eva Maria

Gold Star

Golden Gala

Leaf area, cm2

Figure 2. Leaf area of selected yellow-flowering Magnolias in McMinnville, TN on 9 June 2010.

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Gold Star Stellar Acclaim

SelectionBanana Split 20.0 cdeZ 20.0 fgButterflies 10.0 de 27.0 fgCarlos 13.0 de 17.0 gDaybreak 50.0 ab 90.0 abcElizabeth 10.0 de 25.0 fgEvamaria 45.0 ab 95.0 abGold Star 15.0 de 100.0 aGolden Gala 43.0 abc 60.0 deGolden Gift 20.0 cde 70.0 b-eGolden Sun 60.0 a 65.0 cdeJudy Zuk 17.0 de 30.0 fgLois 20.0 cde 47.0 efSolar Flair 60.0 a 100.0 aStellar Acclaim 47.0 ab 100.0 aSunburst 50.0 ab 80.0 a-dSundance 10.0 de 20.0 fgSun Ray 13.0 de 30.0 fgSun Spire 3.0 e 3.0 gSunsation 43.0 abc 83.0 a-dYellow Bird 63.0 a 90.0 abcYellow Lantern 30.0 bcd 23.0 fgLSD 29 21

% powdery mildew on

individual leaves

% powdery mildew on total leaves per tree

YTreatments followed by the same letter are not significantly different. Means separated using Fisher's protected LSD, α ≤ 0.05.

Figure 3. M. 'Gold Star' and M. 'Stellar Acclaim' foliage with incidence of powdery mildew, photographed September 2010.

Table 3. Percent of powdery mildew incidence on individual leaves and percent of total leaves affected on 16 Aug 2010 with yellow-flowering Magnolia.

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Time of flowering, flowering duration, flower size and color was recorded each spring. Flowering duration is shown in Figures 5 and 6 for 2009 and 2010, respectively. Each yellow bar represents the flowering dura-tion from beginning to end. Often, the peak bloom period is for a short period of time near the middle of the bar. M. ‘Butterflies’ was the earliest to bloom in 2009 and 2010 followed by M. ‘Elizabeth’, which had one of the longest flowering periods during 2009 and 2010. During 2010, spring temperatures were unseasonably warm during the flowering period and flowers matured very quickly; thus, the flowering period was shorter for most selections than in 2009.

Each green bar represents leaf-out from the time the foliage was at least 50% unfurled. Some selections, i.e., M. ‘Sun Spire’, M. ‘Sunburst’ and M. ‘Yellow Bird’ (Figure 7), leafed-out during the flowering period, which masked the impact of the yellow flowers. Observations show the foliage consistently unfurls and fully expands in a short time frame, about 10 to 14 days. The early green foliage thus masks the yellow tepals, regardless of the yellow intensity.

0

10

20

30

40

50

60

70

17-Jun 24-Jun 1-Jul 8-Jul 15-Jul 22-Jul 29-Jul 5-Aug 12-Aug 19-Aug 26-Aug 2-Sep

Perc

ent P

owde

ry M

ildew

on

Tree

Can

opy

Evaluation Date

Butterflies

Elizabeth

Gold Star

Solar Flair

Stellar Acclaim

Figure 4. Powdery mildew rating on 5 selected yellow-flowering Magnolias during 2010.

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Figure 5. Bloom and leaf-out duration of selected yellow-flowering Magnolias in spring 2009. Yellow bars represent the flowering duration and green bars represent the leaf-out period.

Figure 6. Bloom and leaf-out duration of selected yellow-flowering Magnolias in spring 2010. Yellow bars represent the flowering duration and green bars represent the leaf-out period.

Banana Split

Butterfiles

Elizabeth

Gold Star

Golden Gala

Judy Zuk

Lois

Solar Flair

Stellar Acclaim

Sun Burst

Sun Dance

Sun Ray

Sunsation

Yellow Bird

25 Mar 10 14 Apr 10 20 Apr 10 30 Apr 10 6 May 109 Apr 106 Apr 101 Apr 10

Banana Split

Butterfiles

Elizabeth

Gold Star

Golden Gala

Judy Zuk

Lois

Solar Flair

Stellar Acclaim

Sun Burst

Sun Dance

Sun Ray

Sunsation

Yellow Bird

10 Mar 09 6 Apr 09 16 Apr 09 22 Apr 09 28 Apr 09 6 May 0931 Mar 0924 Mar 0918 Mar 09

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Figure 7. Images of selected yellow-flowering Magnolias in McMinnville, Tenn.

Butterflies

Elizabeth

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Golden Gift

Lois

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Solar Flair

Sunburst

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Sunsation

Sun Spire

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A portable spectrophotometer (Minolta 2600d) was used to measure color intensity. Three parameters in the following model represent the lightness of the color: L* at 0 = black and L* at 100 = white; a* with negative val-ues indicate green while positive values indicate magenta and its position between yellow and blue; and b* with negative values indicate blue and positive values indicate yellow (Table 4). The Royal Horticulture Color Chart was used to define tepal color. Samples were read near solar noon on 6 April 2009 and 9 April 2010.

Tepal color varied markedly from the inner side to the outer side and from the basal end to the tip. Some magnolias had flowers with an intrusion of pink and in some cases the prominence of pink overwhelmed the yellow, as seen in M. ‘Coral Lake’, M. ‘Daybreak’ and M. ‘Evamaria’. All reported measurements in this test were made near the center of the tepal on the outer side.

There are differences in the tepal color in this test compared to colors re-ported in the Magnolia Cultivar Checklist and other notable sources (Rob-inson, 2006). This is to be expected due to the maturity of the flower, loca-tion of the plant and expected differences from year to year (Knox, 2001). Since all colors are detected with the spectrophotometer, more precise color intensity can be measured and provide results similar to what the

Yellow Bird

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human eye perceives. Based on the parameter b*, the higher the number, the more yellow the color; therefore M. ‘Judy Zuk’ and M. ‘Yellow Bird’ have the highest yellow reading. M. ‘Sun Spire’, M. ‘Sundance’, M. ‘Gold Star’, M. ‘Golden Gala’ and M. ‘Stellar Acclaim’ had the lightest yellow intensity with b* values of 21.4, 22.2, 22.4, 22.6 and 22.8, respectively.

Conclusion

A comprehensive replicated evaluation of new and familiar yellow-flow-ering magnolias in one location will benefit magnolia connoisseurs, the nursery industry and prospective plant breeders. In time, more valuable information will be collected as the plants mature in this evaluation.

The palette of yellow color is well represented with the Magnolia selections from border-line creamy yellow to distinctly yellow in color (Cover, 2009). However, as yellow-flowering magnolias become more widely known, many selections may be less popular for the common landscape and will serve only as a breeding line for developing improved selections. Time of flowering is critical for plants in US Hardiness Zones 6 and 7. Early spring frost (and freezes) can be detrimental on spring flowering as well as the leaf-out period. In this evaluation, many selections leafed-out during the

Table 4. Color parameters of selected yellow-flowering Magnolias determined by a portable spectrophotometer, Minolta 2600d.

Selection L* a* b* 6 April 2009 9 April 2010Banana Split 73.9 -2.8 28.1 - -Butterflies 73.1 -2.7 32.7 4c -Elizabeth 71.2 -0.6 33.6 2d 4dGold Star 73.5 -2.1 22.4 4d -Golden Gala 74.2 -2.5 22.6 6d -Golden Gift 70.2 -1.2 32.3 6d -Golden Sun 73.1 -2.4 25.0 - -Judy Zuk 66.7 1.8 38.9 - -Lois 72.9 -1.8 28.2 5d 8cSolar Flair 68.8 -3.2 30.6 4c 4cStellar Acclaim 67.4 0.6 22.8 5d -Sun Ray 72.7 -1.0 31.2 2d 4dSun Spire 70.2 -0.8 21.4 - -Sunburst 71.1 -1.3 25.9 5d 6dSundance 75.2 -3.2 22.2 2d 8cSunsation 69.2 -2.3 26.9 6d -Yellow Bird 68.3 -2.1 34.0 5d -

YRoyal Horticultural Colour Chart

RHCYColor parameters,

April 2009Z

ZL* at 0 = black and L* at 100 = white; a* with negative values indicate green while positive values indicate magenta and its position between yellow and blue; and b* with negative values indicate blue and positive values indicate yellow. Spectrophotometer measurements are taken excluding the specular reflection to provide measurement results similar to those observed by the human eye.

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flowering period which caused the flowering to have less impact because the yellow tepals were masked by the early green foliage. This timing, as well as flower color, will be critical to the popular success of many yellow-flowered selections (Tubesing, 1998).

Another issue that needs to be addressed is the compatibility of the root system. Several individual plants have died or are showing signs of graft incompatibility. Swollen stem tissue above and below the bud union is becoming more prevalent as some of the plants mature. Several propaga-tors queried revealed that three root stocks are routinely used: Magnolia ‘Jane’, M. kobus or M. acuminata; however, the root stocks of the plants in this evaluation are not known. Further research is needed to identify the most compatible root stock for the yellow-flowering Magnolia hybrids.

AcknowledgementThis has been an interesting and challenging research project. Many thanks to The Magnolia Society International for funding this research project!

ReferencesCover, S. 2009. The performance of yellow magnolia hybrids in a modi-fied continental climate. Magnolia 44(86):5-17.

Knox, G.W. 2002. Yellow flowering magnolias for Florida and the Gulf Coast. Proc. of the Southern Nursery Assoc Res. Conf. 47:637-639.

Knox, G.W. 2001. New and improved deciduous magnolia cultivars. Comb. Proc. Intl. Prop. Soc. 51:601-603.

Magnolia Society, Inc. 2010. Magnolia Cultivars Checklist, http://www.magnoliasociety.org/checklist_ndx.html (accessed 16 Nov 2010).

Robinson, M. 2006. Yellow magnolias – an English view. Royal Horti-cultural Society. http://www.rhs.org.uk/plants/yellowmagnolias.asp (ac-cessed 7 Feb 2006).

Royal Horticultural Society and Flower Council of Holland. 1986. RHS colour chart. RHS, London, UK.

Tubesing, C. 1998. Sorting out the yellow magnolias. Comb. Proc. Intl. Prop. Soc. 48:312-314.

USDA. 2010. U.S. Department of Agriculture, National Agricultural Sta-tistical Service (USDA-NASS) 2009 Census of Horticultural Specialties. http://www.agcensus.usda.gov. (accessed 17 Nov 2010).

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Ploidy level, genome size, and the music of Magnolias Kevin Parris, Arboretum Director, Spartanburg Community College, Spartanburg, SC

This article is adapted from Parris et al., (2010)

DedicationThis article is dedicated to the visionary breeders of Magnolia that have gone before us, and is presented to those that work today to expand the boundaries and fill in the gaps of a collective genome that surely inspires anyone with an appreciation of plants. The experiences of the recent 2011 MSI Annual Meeting in Providence, RI, were the inspiration I needed to turn the findings of this research into a format that I hope will be embraced by a wonderfully varied audience.

IntroductionUnder the direction of Tom Ranney of North Carolina State University, I began a survey of genome sizes of a wide array of Magnolia taxa in 2008. The study was officially concluded in 2010 for statistical analyses, but will unofficially continue to be amended as additional species, hybrids, and cultivars of interest become available to study.

To understand the reproductive biology of Magnolia species, one must understand polyploidy. Polyploidy is the presence of multiple sets of chromosomes, above the diploid level (2n) within the somatic (vegetative or body) cells of an organism. Polyploidy is extremely rare in animals, but surprisingly common in plants. Magnolias naturally range in ploidy level, with species being either 2n, tetraploid (4n), or hexaploid (6n). Previous sources that include compilations of chromosome counts or ploidy levels used for this study include Callaway, 1994; Chen et al., 2000; Santamour, 1970; and Treseder, 1978. Since we know from chromosome counts that diploid magnolia species have 38 chromosomes, and the haploid gametes (n) have 19, we completely communicate the chromosomal content of a diploid with the expression 2n=2x=38, tetraploid as 2n=4x=76, and hexaploid as 2n=6x=114, with the value before the x representing the complete sets of chromosomes present.

Figure 1: Range of polyploidy in Magnolia.

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This, of course, has significance to breeders because a cross between species of different ploidy levels will favor the higher ploidy parent. This is why the “Little Girl” Hybrids (Magnolia liliiflora (4x) × M. stellata (2x)) most closely resemble the M. liliiflora parent. The greater the difference in ploidy level, the greater the offspring will favor the higher ploidy parent, as evidenced in the Freeman Hybrids (M. grandiflora (6x) x M. virginiana (2x)), which pass as a typical M. grandiflora to all but the most trained eye. When hybrids such as these are developed, we can typically confirm hybridity by closely observing morphological characters. To be certain, chromosome counts can be performed. Since many Magnolia species are polyploids with high chromosome numbers, traditional cytology based upon light microscopic examination is a difficult and time-consuming process. Flow cytometry has proved to be an efficient means of estimating genome size and associated ploidy level (Doležel et al., 2007; Jones et al., 2007). A flow cytometer is essentially a cell counter which can illuminate the stained genetic material within cells. The measured fluorescence generated is displayed in the form of a histogram. We sampled over 300 accessions from various sources that included 62 species, 125 hybrids, and 16 induced polyploids representing taxa from each subgenus of Magnolia as well as both species of Liriodendron, the only other genus in family Magnoliaceae, per Figlar and Nooteboom (2004). Nuclei from newly expanded leaf or tepal tissue were extracted, stained with 4’, 6-diamidino-2-phenylindole (DAPI), and then analyzed (minimum of 2500 nuclei per sample) using a flow cytometer (PA-I; Partec, Münster, Germany) to determine relative holoploid 2C DNA (whole genome) content, following the methods of Jones et al. (2007). Genome sizes were determined by comparing mean relative fluorescence of each sample with an internal standard, Pisum sativum ‘Ctirad’, with a known genome size of 8.76 picograms (one picogram = one trillionth (10-12) of a gram) (Greilhuber et al., 2007). Holoploid, 2C DNA contents were calculated as: 2C = DNA content of standard x (mean fluorescence value of sample ÷ mean fluorescence value of the standard). Because tetraploid Magnolia taxa have similar genome sizes to P. sativum ‘Ctirad’, Magnolia virginiana ‘Jim Wilson’ (3.92 pg) was used as a secondary standard. Therefore, the objectives of this study were to determine the genome sizes and relationships to ploidy levels of a diverse collection of species, hybrids, and cultivars of Magnolia to 1) develop an extensive database of ploidy levels for use by magnolia breeders, 2) determine the

Figure 2: Author running samples through a flow cytometer at the NCSU Mountain Horticultural Crops Research and Extension Center.

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ploidy levels of plants that were chemically treated to artificially induce polyploidy and 3) confirm hybridity of interploid and interspecific (when parents vary substantially in genome size) crosses.

ResourcesThe collection of samples for this study was an extremely rewarding exercise. The NCSU Mountain Crop Improvement Lab was a primary source of accessions. Multiple trips were made to Magnolian Grove Arboretum, the garden of Dick and Anita Figlar. Dick eagerly advised me as I worked my way through samples obtained from the various taxonomic sections of Magnolia. Pat McCracken also generously hosted me on a collection trip and provided samples from numerous taxa. Another substantial contributor of samples was Greg Paige of the Bartlett Tree Research Laboratory, and with the help of David Kruse-Pickler of the San Francisco Botanic Garden I was able to turn a family vacation into a collection opportunity. On another family trip to Washington DC, I was privileged to spend time with Richard Olsen of the U.S. National Arboretum and take a glimpse at the hand-written notes of breeders such as Frank Santamour, William Kosar, and Francis de Vos. Richard also tracked down some significant accessions that led to key findings. Other significant contributions were made from Charles Tubesing of the Holden Arboretum and breeders Dennis Ledvina of Green Bay, Wisconsin, and Bill Smith of Richmond, Virginia. In the past year I have been able to meet both Dennis and Bill and I now know what has driven the likes of these gentlemen and so many others to keep pushing the boundaries of magnolia diversity.

The collection and testing of so many samples may have turned into a painfully repetitive exercise if it were not for the immense respect I have developed for the individuals that brought species into cultivation and

Figure 3: Typical histogram with peaks generated by two samples of differing genome size.

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escorted scores of hybrids into existence. Without their work, this study would have never been possible. Each sample I held was a piece of living history. Nevertheless, I was using modern technology to measure the relative weight of the genetic material present in the average cell of each named plant, thus turning the product of a plant explorer or breeder’s work into a cold number derived from a mathematical equation. Having adventured with friends from the Magnolia Society International to some of the world’s finest assemblies of Magnolia, I recognize these plants are not the outcome of equations. They are the results of nature, combined with the human qualities of hope and frustration, anticipation and tenacity, passion and heartache. But the numbers have consequence, and by better understanding them, greater hope with less heartache may be realized.

Data analysisThe first step in analyzing data was to determine the mean relative genome size of each species and the section they represent (Tables 1 and 2). As expected, a statistical difference in genome size occurs between taxa of differing ploidy levels. This allows us to clearly illustrate the ploidy level of a sample without performing a chromosome count. Also important was the fact that genome size within each species and taxonomic section had insignificant variation. Another important detail to draw from Table 1 is that a statistic difference in genome size can occur between species of different taxonomic sections within the same ploidy level. For example, hybridity can be confirmed in a group of seedlings from a cross between Magnolia virginiana (Section Magnolia) and Magnolia insignis (Section Manglietia) when the plants are large enough to spare just a small portion of one leaf, before intermediate morphological characters become pronounced. This can save breeders the time and expense of cultivating errant progeny to maturity.

Table 2 is condensed in this article to display only the means for each species, rather than reporting all cultivars surveyed. In the case of M. virginiana and M. grandiflora, numerous cultivars were surveyed, with no significance in genome size found. In other species with obscure availability, such as M. sinica, the mean genome size reported is derived from only one accession. Under M. grandiflora, several cultivars previously

Bill Smith and Kevin Parris with some of Bill’s new hybrid seedlings at Lewis Ginter Botanic Garden, May 2011.

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reported to be interploid hybrids are listed to clarify their confirmed ploidy level and species designation. The cultivar ‘Charles Dickens’ has been suggested to have been the result of a cross between M. grandiflora and M. macrophylla (2n=2x=38), but it is hexaploid, aligning it entirely with M. grandiflora. 'Griffin', 'Riegel', and 'Sweet Summer’ are three cultivars which were also thought to have been of hybrid origin, but their genome size is consistent with other M. grandiflora cultivars. Had they been the product of a cross with M. virginiana, their genome size would have been that of a tetraploid.

Table 3 summarizes the results of many hybrids that were surveyed. The results were enlightening. Evidence for successful hybridization between plants of different ploidy levels was apparent based on analysis of genome sizes. In many cases interploid hybrids were substantiated. These include the following within subgenus Magnolia: (M. grandiflora (6x) × M. virginiana (2x)) ‘Maryland’ with an intermediate genome size of 7.49 pg, and also a seedling of ‘Maryland’ from Magnolian Grove Arboretum which was likely open pollinated by M. grandiflora. This accession had a genome size of 9.00 pg, consistent with a pentaploid derived from a (4x × 6x) cross. An unnamed plant at the U.S. National Arboretum with similar appearance to M. ‘Maryland’ was found to have a genome size of 5.62 pg, consistent with a triploid, suggesting a hybrid of M. grandiflora (6x) x M. virginiana (2x) had been backcrossed to M. virginiana. An intermediate tetraploid condition was determined for M. insignis (2x) × M. grandiflora

‘Kay Parris’ (6x) which had an 8.50 pg relative genome size. In addition to the M. virginiana × M. insignis cross mentioned earlier, the following

Figure 4: Histograms illustrating discernable and indiscernible peaks.

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interspecific, intraploid hybrids were confirmed by intermediate size; M. yuyuanensis × M. virginiana, M. ‘Silk Road’ × insignis, and very recently (not included in Table 3) M. insignis × M. fraseri. Within subgenus Yulania, confirmed interploid hybrids were numerous. Verification of hybridity was readily confirmed for the U.S. National Arboretum’s Kosar/de Vos hybrids. M. liliiflora (4x) × M. stellata (2x) had genome sizes ranging from 6.28 to 6.69 pg, consistent with triploids. Numerous putative pentaploid hybrid cultivars, derived from crosses of (6x × 4x) species or hybrids, were also verified. These hybrids include: ‘Alexandrina’, ‘Angelica’, Apollo’, ‘Blushing Belle’, ‘Butterflies’, ‘Elizabeth’, ‘Galaxy’, ‘Gold Finch’ and ‘Spectrum’ with 2C genome sizes ranging from 10.11 to 11.02 pg.

Hybrids arising from parents with odd ploidy levels (5x or aneuploids) were prevalent and had highly variable genome sizes. Magnolia ×soulangeana, a pentaploid hybrid between M. denudata (6x) and M. liliiflora (4x) exhibits fertility in initial F1 hybrids and subsequent generations (McDaniel, 1968), and, when used as parents, gave rise to apparent aneuploid progeny ranging from ~4.6 to ~8.5x, based on genome size. Fertility among M. ×soulangeana cultivars has been examined previously and it was found that pollen viability generally increased with increasing ploidy level above 5x (Santamour, 1970). Relative 2C genome sizes determined here support cytological findings by Santamour (1970) that the cultivars

‘Lennei’ and ‘Grace McDade’ are septaploid (7x) or higher. Other taxa in Table 3 of approximately septaploid genome size include M. ‘Andre Leroy’, M. ‘Manchu Fan’, M. ‘Sunsation’, and M. ‘Todd Gresham’. Each of these hybrids has a parental combination that theoretically could yield 7x offspring. Unreduced gametes can lead to higher than expected genome sizes or ploidy levels in Magnolia hybrids (McDaniel, 1968; Santamour, 1970). In subgenus Yulania, the relative genome size of M. acuminata (4x) × M. stellata (2x) ‘Gold Star’ was determined to be 8.22 pg, consistent with the genome size of a tetraploid. This suggests this cultivar is the result of pollination from an unintended source, or the product of an unreduced

Flow cytometry was used to verify this seedling was tetraploid (8.50 pg), confirming the first successful cross between M. insignis and M. grandiflora.

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36

gamete from M. stellata. The realization that M. ‘Gold Star’ is tetraploid explains why it has been successfully used as a fertile parent in several crosses. No triploid hybrids were found to be parents of any hybrid surveyed in this study, indicating triploids may typically not be fertile.

Table 4 documents the confirmation of several induced polyploids. In some cases, the artificial induction of polyploidy in Magnolia also can enhance ornamental characteristics, including thicker leaves and larger flowers with thicker petals that persist longer (Kehr, 1985). Crosses between species with varying ploidy levels may yield hybrids with nonstandard chromosome numbers that can result in reduced fertility or sterility. Because of these constraints, Magnolia breeders have attempted to induce new polyploids to overcome these limitations, yet most of these putative polyploids have never been confirmed. The most notable clarification provided by this study was the ploidy level of M. sieboldii ‘Colossus’, long thought to be hexaploid, yet multiple accessions from multiple sources were found to be diploid. This revelation, coupled with the discovery that M. ‘Sweet Summer’ is not a tetraploid hybrid, sheds light on the reason a cross between M. sieboldii ‘Colossus’ and M. ‘Sweet Summer’ (genome size documented in Table 2) so closely resembles M. grandiflora. Instead of a 6x × 4x cross that should have resulted in 5x hybrid with more intermediate characteristics, this was really a 2x × 6x cross heavily favoring the higher ploidy level of M. grandiflora. Another most interesting discovery was a cytochimera (tissue composed of cells with differing ploidy levels) of M. grandiflora ‘Little Gem’, created by Bob Head of Seneca, SC, by treating young rooted cuttings with oryzalin. The specimen was induced 10 years prior, and 55% of the cells in the examined tissue had remained dodecaploid (2n=12x=228). Multiple accessions of M. cylindrica (8x) and M. stellata (4x) from the Holden Arboretum were also confirmed as induced polyploids.

In order to demonstrate the reliability of flow cytometry as a means to discern ploidy level, standard cytology was performed on a seedling of uncertain parentage. Actively growing root tips of container grown seedlings of putative octaploid M. cylindrica were collected at midday and placed in the mitotic inhibitor, 8-hydroxyquinoline for 2 h at 5 °C in dark conditions. The source of this seed was the Holden Arboretum via the Seed Counter of the Magnolia Society International. They were then transferred to a fixative solution of 3 parts 95% ethanol: 1 part glacial acetic acid (v/v) for 24 h, while remaining at 5 °C in dark conditions. Tissue was excised from just behind the root tip and placed in 12N HCl for 10 s. Squashes were prepared with a small amount of this tissue and a drop of modified Fuelgen stain on a slide with a cover slip. A chromosome count of one of these seedlings, SCC 2009-004, identified approximately 133 chromosomes (2n=7x=133) (Fig. 5), in close agreement with genome size data (14.92 pg) which was determined to be approximately 7x (6.7x). This supports the

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assertion of Charles Tubesing (in MSI Seed Counter information) that the octoploids could have outcrossed with other magnolias with lower ploidy levels from their collections.

ConclusionFor me, this study has painted an abstract picture of the dance that takes place when gametes from Magnolias meet. Within species the match is so perfect that little or no genetic information is lost or gained that would lead to significant variation in genome size. The partners are well acquainted, the dance is well rehearsed, no toes are stepped on, and the performance is flawless. Yet, we have learned that Magnolia species may dance with different partners. Though they may have been separated by mountains, plains, or oceans, and eons of time, there is an affinity that still exists. The harmony of the genetic sequences rings like a musical composition. Therefore, the tune is familiar, and though the partners may stumble, the jubilation of the reunion often shines through in the dance.

For breeders, the revised taxonomy by Figlar and Nooteboom (2004), along with molecular data presented by Azuma et al. (1999, 2000, 2001) and Kim et al. (2001), provides a greater understanding of the relatedness and potential for interspecific hybridizations among closely allied species that is often supported empirically in Table 3 of this paper. Yet, development of progeny from hybrids, beyond an F1 generation, requires genome/chromosomal compatibility for meiosis to function properly. Thus, it is reasonable to expect that the greater the difference in genome size among parental species, the less likely hybrid progeny will be fertile. The results of this study have provided data on genome sizes and ploidy levels of Magnolia, confirmation of hybrids and induced polyploids, comparison of methods for determining genome size, and insights into reproductive biology that will help facilitate the development of improved hybrids in the future. If plants are developed with the inspiration of sound science

Figure 5: Photomicrograph of a root tip cell of Magnolia SCC 2009-004 in early metaphase, with approximately 133 chromosomes. Maternal parent Magnolia cylindrica (2n=8x=152), paternal parent unknown, but likely (2n=6x=114), resulting in a plant that is 7x

Magnolia

38

and a creative eye, they will grace gardens beyond the life of the breeder, just like the melody of a classic song can transcend generations.

Below is some of the sheet music, let us continue the song and dance.Table 1. Summary of means and ranges for 2C, holoploid genome size (pg) and 1Cx monoploid genome size (pg) of Magnolia spp. grouped by section and ploidy level.

Ploidy level z

Classification 2n = 2x = 38 2n = 4x = 76 2n = 6x = 114

Subgenus Magnolia

Section Magnolia (5/41y)

2C = 3.80xEw

(3.43 - 4.40) u

1CX = 1.90t

(1.72 - 2.20) s

Nv 2C = 11.18 C

(10.83 - 11.86)

1CX = 1.86

(1.81 - 1.98)

Section Gwillimia (4/6)

2C = 5.32 A

(5.10 - 5.63)

1CX = 2.66

(2.41 - 2.82)

N N

Section Rhytidospermum (5/18)

2C = 4.27 CD

(3.66 - 4.69)

1CX = 2.14

(1.83 - 2.35)

N N

Section Manglietia (10/17) 2C = 4.87 B

(4.65 - 5.25)

1CX = 2.44

(2.33 - 2.63)

N N

Section Macrophylla (1/5) 2C = 4.57 BC

(4.41 - 4.87)

1CX = 2.28

(2.21 - 2.44)

N N

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Section Auriculata (1/3) 2C = 3.83 E

(3.74 - 3.96)

1CX = 1.94

(1.87 - 1.98)

N N

Section Kmeria (1/1) 2C = 5.51 A

(5.51 - 5.51)

1CX = 2.76

(2.76 - 2.76)

N N

Subgenus Yulania

Section Yulania (14/43)

2C = 4.05 DE

(3.84 - 4.26)

1CX = 2.02

(1.92 - 2.13)

2C = 8.56 A

(8.08 - 9.34)

1CX = 2.14

(2.02 - 2.34)

2C = 12.68 A

(11.49 - 13.47)

1CX = 2.11

(1.92 - 2.25)

Section Michelia (17/31) 2C = 4.56 BC

(4.23 - 4.92)

1CX = 2.28

(2.11 - 2.46)

N

N

Subgenus Gynopodium

Section Gynopodium (2/3)

Section Manglietiastrum (1/1)

N

2C = 4.21 D

(4.21 - 4.21)

1CX = 2.11

(2.11 - 2.11)

N

N

2C = 11.93 B

(11.57 - 12.50)

1CX = 1.99

(1.93 - 2.08)

N

Genus Liriodendron (2/2) 2C = 3.41 F

(3.35 - 3.47)

1CX = 1.71

(1.68 - 1.74)

N N

z Taxa assigned to given ploidy level based on estimated genome sizes and in agreement with

published chromosome counts, if available.

y Numbers in parentheses, following classifications, indicate the number of species

sampled, and the total number of taxa within those species sampled.

x Relative 2C genome sizes (pg) were determined using 4’,6-diamidino-2-phenylindole as the

flourochrome stain.

w Letters following Relative 2C genome sizes, within a column, are significantly different,

using the Waller Procedure(Proc GLM, SAS version 9.1; SAS Institute, Cary, NC) for

means separation, at P < 0.05.

Magnolia

40

Section Gynopodium (2/3)

Section Manglietiastrum (1/1)

N

2C = 4.21 D

(4.21 - 4.21)

1CX = 2.11

(2.11 - 2.11)

N

N

2C = 11.93 B

(11.57 - 12.50)

1CX = 1.99

(1.93 - 2.08)

N

Genus Liriodendron (2/2) 2C = 3.41 F

(3.35 - 3.47)

1CX = 1.71

(1.68 - 1.74)

N N

z Taxa assigned to given ploidy level based on estimated genome sizes and in agreement with

published chromosome counts, if available.

y Numbers in parentheses, following classifications, indicate the number of species

sampled, and the total number of taxa within those species sampled.

x Relative 2C genome sizes (pg) were determined using 4’,6-diamidino-2-phenylindole as the

flourochrome stain.

w Letters following Relative 2C genome sizes, within a column, are significantly different,

using the Waller Procedure(Proc GLM, SAS version 9.1; SAS Institute, Cary, NC) for

means separation, at P < 0.05.

z Taxa assigned to given ploidy level based on estimated genome sizes and in agreement with

published chromosome counts, if available.

y Numbers in parentheses, following classifications, indicate the number of species

sampled, and the total number of taxa within those species sampled.

x Relative 2C genome sizes (pg) were determined using 4’,6-diamidino-2-phenylindole as the

flourochrome stain.

w Letters following Relative 2C genome sizes, within a column, are significantly different,

using the Waller Procedure(Proc GLM, SAS version 9.1; SAS Institute, Cary, NC) for

means separation, at P < 0.05.

v N = No genome size reported; indicates given ploidy level was not reported or observed in this

section.

u Values represent ranges of 2C genome size for all Magnolia spp. sampled in each section.

t Relative 1Cx mean genome sizes (pg) were calculated as: (2C mean / ploidy level).

s Values represent ranges of 1CX genome size means for all Magnolia spp. sampled in each section.

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Table 2. Relative genome size (pg) and estimated ploidy level for a diverse collection of Magnoliaceae representing 62 species.

delavayii 5.28 2.64 2

Subsection Blumiana

hodgsonii 5.47 2.73 2

liliifera 5.63 2.82 2

Section Rhytidospermum

Subsection Rhytidospermum

obovata (hypoleuca) 3.97 1.99 2

officinalis var. officinalis 4.01 2.00 2

officinalis var. biloba 3.72 1.86 2

rostrata 4.69 2.35 2

tripetala 4.00 2.00 2

Subsection Oyama

sieboldii including ‘Colossus’ 4.50 2.25 2

Section Manglietia

aromatica 5.15 2.58 2

changhungtana (pachyphylla) 4.69 2.35 2

conifera var. chingii 4.87 2.34 2

fordiana 4.81 2.41 2

garrettii 5.25 2.63 2

hookeri 4.82 2.41 2

insignis 4.94 2.47 2

kwangtungensis (moto) 4.65 2.33 2

ovoidea 5.02 2.51 2

yuyuanensis 4.74 2.37 2

Section Macrophylla

macrophylla var. macrophylla 4.56 2.28 2

Taxa Cultivar/selection

Mean

Relative 2C

genome size

(pg) z

Mean relative

1Cx

genome size by

species (pg) y

Ploidy

level (x)

Subgenus Magnolia

Section Magnolia

virginiana var. virginiana including 3.72 1.86 2

R14-397 (thought to be tetraploid)

virginiana var. australis 3.73

grandiflora including 11.22 1.87 6

‘Charles Dickens’ (suggested

hybrid w/ macrophylla)

'Griffin' (suggested hybrid w/

virginiana)

‘Riegel’ (suggested hybrid w/

virginiana)

‘Sweet Summer’ (suggested hybrid

w/ virginiana)

guatamalensis 4.37 2.19 2

sharpii 4.40 2.20 2

tamaulipana 11.28 1.88 6

Section Gwillimia

Subsection Gwillimia

coco 4.83 2.42 2

Magnolia

42

liliifera 5.63 2.82 2

Section Rhytidospermum

Subsection Rhytidospermum

obovata (hypoleuca) 3.97 1.99 2

officinalis var. officinalis 4.01 2.00 2

officinalis var. biloba 3.72 1.86 2

rostrata 4.69 2.35 2

tripetala 4.00 2.00 2

Subsection Oyama

sieboldii including ‘Colossus’ 4.50 2.25 2

Section Manglietia

aromatica 5.15 2.58 2

changhungtana (pachyphylla) 4.69 2.35 2

conifera var. chingii 4.87 2.34 2

fordiana 4.81 2.41 2

garrettii 5.25 2.63 2

hookeri 4.82 2.41 2

insignis 4.94 2.47 2

kwangtungensis (moto) 4.65 2.33 2

ovoidea 5.02 2.51 2

yuyuanensis 4.74 2.37 2

Section Macrophylla

macrophylla var. macrophylla 4.56 2.28 2

macrophylla var. ashei 4.52 2.26 2

macrophylla var. dealbata 4.87 2.44 2

Section Auriculata

fraseri var. fraseri 3.94 1.97 2

fraseri var. pyramidata 3.74 1.87 2

Section Kmeria

thailandica 5.51 2.76 2

Subgenus Yulania

Section Yulania

Subsection Yulania

amoena 4.26 2.13 2

biondii 4.12 2.06 2

campbellii 12.54 2.09 6

cylindrica 8.92 2.23 4

dawsoniana 13.12 2.19 6

denudata 13.26 2.21 6

kobus 4.04 2.02 2

liliiflora 9.34 2.28 4

sargentiana 11.49 1.92 6

sprengeri 12.66 2.11 6

salicifolia 3.91 1.96 2

stellata including 3.94 1.97 2

‘Two Stones’ (reported tetraploid)

zenii 4.16 2.08 2

Subsection Tulipastrum

acuminata 8.24 2.06 4

acuminata var. subcordata 8.27 2.07 4

Section Michelia

cavaleriei var. platypetala 4.40 2.19 2

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fraseri var. fraseri 3.94 1.97 2

fraseri var. pyramidata 3.74 1.87 2

Section Kmeria

thailandica 5.51 2.76 2

Subgenus Yulania

Section Yulania

Subsection Yulania

amoena 4.26 2.13 2

biondii 4.12 2.06 2

campbellii 12.54 2.09 6

cylindrica 8.92 2.23 4

dawsoniana 13.12 2.19 6

denudata 13.26 2.21 6

kobus 4.04 2.02 2

liliiflora 9.34 2.28 4

sargentiana 11.49 1.92 6

sprengeri 12.66 2.11 6

salicifolia 3.91 1.96 2

stellata including 3.94 1.97 2

‘Two Stones’ (reported tetraploid)

zenii 4.16 2.08 2

Subsection Tulipastrum

acuminata 8.24 2.06 4

acuminata var. subcordata 8.27 2.07 4

Section Michelia

cavaleriei var. platypetala 4.40 2.19 2

champaca 4.74 2.37 2

chapensis 4.92 2.46 2

doltsopa 4.52 2.26 2

ernestii 4.50 2.25 2

figo var. figo 4.58 2.29 2

figo var. skinneriana 4.48 2.24 2

figo var. crassipes 4.71 2.36 2

floribunda 4.51 2.26 2

foveolata var. foveolata ‘Shibamichi’ 4.23 2.12 2

foveolata var. cinerascens 4.42 2.21 2

fulva var. calcicola 4.61 2.31 2

laevifolia 4.56 2.28 2

lanuginosa 4.80 2.40 2

maudiae 4.56 2.28 2

martini 4.75 2.38 2

odora 4.54 2.27 2

shiluensis 4.49 2.25 2

sirindhorniae 4.53 2.27 2

Subgenus Gynopodium

Section Gynopodium

lotungensis 11.54 1.93 6

yunnanensis Vietnam origin 12.50 2.08 6

Section Manglietiastrum

sinica 4.21 2.11 2

Genus Liriodendron

chinensis 3.47 1.74 2

Magnolia

44

champaca 4.74 2.37 2

chapensis 4.92 2.46 2

doltsopa 4.52 2.26 2

ernestii 4.50 2.25 2

figo var. figo 4.58 2.29 2

figo var. skinneriana 4.48 2.24 2

figo var. crassipes 4.71 2.36 2

floribunda 4.51 2.26 2

foveolata var. foveolata ‘Shibamichi’ 4.23 2.12 2

foveolata var. cinerascens 4.42 2.21 2

fulva var. calcicola 4.61 2.31 2

laevifolia 4.56 2.28 2

lanuginosa 4.80 2.40 2

maudiae 4.56 2.28 2

martini 4.75 2.38 2

odora 4.54 2.27 2

shiluensis 4.49 2.25 2

sirindhorniae 4.53 2.27 2

Subgenus Gynopodium

Section Gynopodium

lotungensis 11.54 1.93 6

yunnanensis Vietnam origin 12.50 2.08 6

Section Manglietiastrum

sinica 4.21 2.11 2

Genus Liriodendron

chinensis 3.47 1.74 2

tulipifera 3.35 1.68 2

z Genome sizes were determined using 4’,6-diamidino-2-phenylindole as the flourochrome stain. Values are means of

multiple samples, and often from multiple cultivars, accessions or sources.

y1CX values were calculated as: [(2C value / ploidy level)

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Table 3. Relative genome size (pg) and estimated ploidy level for interspecific hybrids of Magnolia arranged by reported parentage ploidy levels.

Reported parentage Cultivar/selection Mean

Relative 2C

Genome

size (pg)z

Weighted 1CX

Genome size

(pg)y

Reported

parental

Ploidy

levels (x)x

Estimated ploidy

level (x)w

Subgenus Magnolia

Intraploid Hybrids

2n=2x=38

insignis × virginiana 'Katie-O' 4.30 2.15 2×2 2

macrophylla × tripetala 3.68 2.12 2×2 2

obovata × virginiana 'Nimbus' 3.79 1.93 2×2 2

officinalis × tripetala 3.96 1.95 2×2 2

sieboldii 'Colossus' × insignis 4.60 2.37 2×2 2

sieboldii 'Colossus' × insignis 4.63 2.37 2×2 2

sieboldii 'Genesis' × virginiana R10-24 4.06 2.06 2×2 2

×thompsoniana (=virginiana × tripetala) 3.95 1.93 2×2 2

'Silk Road' ((tripetala × obovata) × tripetala))

× insignis 4.35 2.23 2×2 2

yuyuanensis × insignis 4.53 2.43 2×2 2

yuyuanensis × sieboldii 104/1 4.67 2.32 2×2 2

yuyuanensis × virginiana 4.41 2.12 2×2 2

virginiana ’Havener’ × insignis (Red Form) 111/7 4.23 2.17 2×2 2

Interploid Hybrids

2n=3x=57

(grandiflora × virginiana) × virginiana 5.62 1.87 4×2 3

2n=4x=76

grandiflora × virginiana 'Maryland' 7.52 1.87 6×2 4

insignis × grandiflora 'Kay Parris' 8.53 2.02 2×6 4

sieboldii 'Colossus' × grandiflora 'Bracken’s

Brown Beauty’ 7.87 1.97 2×6 4

sieboldii 'Colossus' × grandiflora 'Kay Parris' 8.23 1.97 2×6 4

sieboldii 'Colossus' × 'Sweet Summer' 8.02 1.97 2×6 4

sieboldii 'Pride of Norway' × 'Sweet Summer' 7.99 1.97 2×6 4

2n=5x=95

'Maryland' (grandiflora × virginiana) ×

grandiflora

(Maryland

Seedling) 9.00 1.87 4×6 5

Subgenus Yulania

Intraploid Hybrids

2n=2x=38

×kewensis (=kobus × salicifolia)

'Wada's

Memory' 3.83 1.99 2×2 2

×loebneri (=kobus × stellata) ‘Donna’ 5.86 2.00 2×2 3

'Pink Superstar' 4.02 2.00 2×2 2

'Leonard

Messel' 4.00 2.00 2×2 2

'Mag's

Pirouette' 3.97 2.00 2×2 2

'Merril' 3.86 2.00 2×2 2

'Spring Snow’ 3.86 2.00 2×2 2

'Wildcat' 3.98 2.00 2×2 2

×alba (=champaca × montana) 4.81 2.28 2×2 2

Magnolia

46

2n=4x=76

grandiflora × virginiana 'Maryland' 7.52 1.87 6×2 4

insignis × grandiflora 'Kay Parris' 8.53 2.02 2×6 4

sieboldii 'Colossus' × grandiflora 'Bracken’s

Brown Beauty’ 7.87 1.97 2×6 4

sieboldii 'Colossus' × grandiflora 'Kay Parris' 8.23 1.97 2×6 4

sieboldii 'Colossus' × 'Sweet Summer' 8.02 1.97 2×6 4

sieboldii 'Pride of Norway' × 'Sweet Summer' 7.99 1.97 2×6 4

2n=5x=95

'Maryland' (grandiflora × virginiana) ×

grandiflora

(Maryland

Seedling) 9.00 1.87 4×6 5

Subgenus Yulania

Intraploid Hybrids

2n=2x=38

×kewensis (=kobus × salicifolia)

'Wada's

Memory' 3.83 1.99 2×2 2

×loebneri (=kobus × stellata) ‘Donna’ 5.86 2.00 2×2 3

'Pink Superstar' 4.02 2.00 2×2 2

'Leonard

Messel' 4.00 2.00 2×2 2

'Mag's

Pirouette' 3.97 2.00 2×2 2

'Merril' 3.86 2.00 2×2 2

'Spring Snow’ 3.86 2.00 2×2 2

'Wildcat' 3.98 2.00 2×2 2

×alba (=champaca × montana) 4.81 2.28 2×2 2

laevifolia × figo (Clifford Parks) 4.46 2.28 2×2 2

×foggii (=figo × doltsopa) 4.53 2.27 2×2 2

2n=4x=76

acuminata 'Busey' × acuminata sub. 'Miss

Honeybee' 'Miranja' 18.25 2.10 4×4 ~8.6

liliiflora 'O'Neill' × kobus 'Norman Gould' ‘Roseanne’ 8.53 2.15 4×4 4

×brooklynensis 'Woodsman' × 'Gold Star'

(acuminata ‘Miss Honeybee’ × stellata) 'Solar Flair' 8.19 2.13 4×4 4

×brooklynensis 'Woodsman' ×'Gold Star'

(acuminata ‘Miss Honeybee’ × stellata) 'Sunburst' 8.07 2.13 4×4 4

×brooklynensis ‘Woodsman’ בGold Star’

(acuminata ‘Miss Honeybee’ × stellata) 'Tranquility' 8.15 2.13 4×4 4

×brooklynensis (=acuminata × liliiflora) 'Woodsman' 8.21 2.17 4×4 4

2n=6x=114

denudata × sprengeri 'Diva' 'Legacy' 13.11 2.16 6×6 6

sargentii var. robusta × campbellii 'Hawk' 12.67 2.01 6×6 6

×veitchii (=campbellii × denudata) 12.96 2.15 6×6 6

Interploid Hybrids

cylindrica × ×veitchii 'Peter Veitch' 'Albatross' 11.14 2.18 4×6 5

×soulangeana (=denudata × liliiflora) 'Alexandrina' 10.70 2.24 6×4 5

×soulangeana (=denudata × liliiflora) 'Andre Leroy' 14.60 2.24 ? ×? ~6.5

cylindrica × denudata 'Sawada's Pink' 'Angelica' 10.83 2.22 4×6 5

stellata × liliiflora 'Nigra' 'Ann' 6.28 2.18 2×4 3

liliiflora × cambellii 'Lanarth' 'Apollo' 11.02 2.17 4×6 5

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'Vulcan' (campbellii 'Lanarth' × liliiflora) ×

×soulangeana 'Lennei' ArborTree Select 16.97 2.21 5×~8 ~7.7

×soulangeana 'Lennei Alba' × 'Mark Jury'

(campbellii ‘Lanarth’ × sargentiana) 'Athene' 14.96 2.14 ~7.6×6 ~7

×soulangeana 'Lennei' × 'Mark Jury'

(campbellii ‘Lanarth’ × sargentiana) 'Atlas' 12.82 2.14 ~8×6 ~6

stellata 'Rosea' × liliiflora 'Nigra' 'Betty' 6.61 2.18 2×4 3

‘Yellow Bird' (acuminata × ×brooklynensis

‘Evamaria’) × 'Caerhays Belle' (sargentiana ×

sprengeri ‘Diva’) 'Blushing Belle' 10.32 2.11 4×6 5

acuminata × denudata 'Sawada's Cream' 'Butterflies' 10.71 2.15 4×6 5

‘Legend’ × ‘Butterflies’ 'Coral Lake' 12.09 2.15 5×5 ~5.6

×veitchii × ×soulangeana 'David Clulow' 16.75 2.19 6×? ~7.6

×brooklynensis 'Woodsman' × 'Tina Durio'

(×soulangeana ‘Lennei Alba’ × ×veitchii) 'Daybreak' 10.71 2.20 4×~6.9 ~4.9

acuminata × denudata 'Elizabeth' 10.59 2.15 4×6 5

denudata × stellata 'Waterlily' 'Emma Cook' 10.26 2.15 6×2 ~4.8

kobus 'Norman Gould' × ×soulangeana

'Lennei’ 'Eskimo' 9.99 2.14 4×~8 ~4.6

sprengeri 'Diva' × ×soulangeana 'Wada’s

Picture' 'Felicity' 10.75 2.18 6×5 ~4.9

×soulangeana 'Deep Purple Dream’ × 'Paul

Cook' 'Frank's Masterpiece' 14.66 2.19 ?×6 ~6.7

×soulangeana (=denudata × liliiflora) 'Fukuju' 19.02 2.24 ?×? ~8.5

liliiflora 'Nigra’ × sprengeri 'Diva' 'Galaxy' 10.45 2.18 4×6 5

acuminata var. sub. 'Miss Honeybee' × 'Gold Finch' 10.81 2.15 4×6 5.0

laevifolia × figo (Clifford Parks) 4.46 2.28 2×2 2

×foggii (=figo × doltsopa) 4.53 2.27 2×2 2

2n=4x=76

acuminata 'Busey' × acuminata sub. 'Miss

Honeybee' 'Miranja' 18.25 2.10 4×4 ~8.6

liliiflora 'O'Neill' × kobus 'Norman Gould' ‘Roseanne’ 8.53 2.15 4×4 4

×brooklynensis 'Woodsman' × 'Gold Star'

(acuminata ‘Miss Honeybee’ × stellata) 'Solar Flair' 8.19 2.13 4×4 4

×brooklynensis 'Woodsman' ×'Gold Star'

(acuminata ‘Miss Honeybee’ × stellata) 'Sunburst' 8.07 2.13 4×4 4

×brooklynensis ‘Woodsman’ בGold Star’

(acuminata ‘Miss Honeybee’ × stellata) 'Tranquility' 8.15 2.13 4×4 4

×brooklynensis (=acuminata × liliiflora) 'Woodsman' 8.21 2.17 4×4 4

2n=6x=114

denudata × sprengeri 'Diva' 'Legacy' 13.11 2.16 6×6 6

sargentii var. robusta × campbellii 'Hawk' 12.67 2.01 6×6 6

×veitchii (=campbellii × denudata) 12.96 2.15 6×6 6

Interploid Hybrids

cylindrica × ×veitchii 'Peter Veitch' 'Albatross' 11.14 2.18 4×6 5

×soulangeana (=denudata × liliiflora) 'Alexandrina' 10.70 2.24 6×4 5

×soulangeana (=denudata × liliiflora) 'Andre Leroy' 14.60 2.24 ? ×? ~6.5

cylindrica × denudata 'Sawada's Pink' 'Angelica' 10.83 2.22 4×6 5

stellata × liliiflora 'Nigra' 'Ann' 6.28 2.18 2×4 3

liliiflora × cambellii 'Lanarth' 'Apollo' 11.02 2.17 4×6 5

denudata 'Sawada's Cream'

acuminata × denudata 'Golden Sun' 13.59 2.15 4×6 ~6.3

acuminata × stellata ‘Gold Star’ 8.22 2.06 4×2 4

×soulangeana (=denudata × liliiflora) 'Grace McDade' 17.35 2.24 ?×? ~7.8

(×brooklynensis ‘Woodsman’ × ×soulangeana

'Lennei') × 'Elizabeth' (acuminata × denudata) 'Green Snow' 11.47 2.20 (4×~8)×5 ~5.2

×brooklynensis 'Woodsman' × 'Elizabeth'

(acuminata × denudata) 'Hot Flash' 8.43 2.15 4×5 ~3.9

'Mark Jury' (campbellii ‘Lanarth’ ×

sargentiana) × ×soulangeana 'Lennei' 'Iolanthe' 13.62 2.14 6×~8 ~6.4

acuminata × denudata 'Ivory Chalice' 10.76 2.17 4×6 5

×soulangeana × ×veitchii 'Jon Jon' 15.16 2.19 ?×6 ~6.9

×loebneri ‘Encore’ × ×soulangeana

‘Alexandrina’ Kehr Seedling 10.92 2.17 2×~5 ~5

acuminata × denudata 'Legend' 10.77 2.15 4×6 5

×soulangeana (=denudata × liliiflora) 'Lennei' 17.89 2.24 ?×? ~8

×soulangeana (=denudata × liliiflora) 'Lennei Alba' 16.91 2.24 ?×? ~7.6

acuminata var. subcordata × ×soulangeana 'Big

Pink' 'Limelight' 14.23 2.18 4×? ~6.5

acuminata × (acuminata × denudata) 'Lois' 14.61 2.10 4×5 ~7.0

×soulangeana × ×veitchii 'Manchu Fan' 14.86 2.19 ?×6 ~6.8

(liliiflora × cylindrica) × ×soulangeana 'Ruby' 'March till Frost' 12.89 2.25 4×? ~5.7

×soulangeana 'Lennei' × 'Paul Cook'

(×soulangeana ‘Lennei’ seedling × sprengeri

‘Diva’) 'Millie Gaylon' 14.20 2.21 ~8×(?×6) ~6.4

stellata × liliiflora 'Orchid' 2.18 2×4 3

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denudata 'Sawada's Cream'

acuminata × denudata 'Golden Sun' 13.59 2.15 4×6 ~6.3

acuminata × stellata ‘Gold Star’ 8.22 2.06 4×2 4

×soulangeana (=denudata × liliiflora) 'Grace McDade' 17.35 2.24 ?×? ~7.8

(×brooklynensis ‘Woodsman’ × ×soulangeana

'Lennei') × 'Elizabeth' (acuminata × denudata) 'Green Snow' 11.47 2.20 (4×~8)×5 ~5.2

×brooklynensis 'Woodsman' × 'Elizabeth'

(acuminata × denudata) 'Hot Flash' 8.43 2.15 4×5 ~3.9

'Mark Jury' (campbellii ‘Lanarth’ ×

sargentiana) × ×soulangeana 'Lennei' 'Iolanthe' 13.62 2.14 6×~8 ~6.4

acuminata × denudata 'Ivory Chalice' 10.76 2.17 4×6 5

×soulangeana × ×veitchii 'Jon Jon' 15.16 2.19 ?×6 ~6.9

×loebneri ‘Encore’ × ×soulangeana

‘Alexandrina’ Kehr Seedling 10.92 2.17 2×~5 ~5

acuminata × denudata 'Legend' 10.77 2.15 4×6 5

×soulangeana (=denudata × liliiflora) 'Lennei' 17.89 2.24 ?×? ~8

×soulangeana (=denudata × liliiflora) 'Lennei Alba' 16.91 2.24 ?×? ~7.6

acuminata var. subcordata × ×soulangeana 'Big

Pink' 'Limelight' 14.23 2.18 4×? ~6.5

acuminata × (acuminata × denudata) 'Lois' 14.61 2.10 4×5 ~7.0

×soulangeana × ×veitchii 'Manchu Fan' 14.86 2.19 ?×6 ~6.8

(liliiflora × cylindrica) × ×soulangeana 'Ruby' 'March till Frost' 12.89 2.25 4×? ~5.7

×soulangeana 'Lennei' × 'Paul Cook'

(×soulangeana ‘Lennei’ seedling × sprengeri

‘Diva’) 'Millie Gaylon' 14.20 2.21 ~8×(?×6) ~6.4

stellata × liliiflora 'Orchid' 2.18 2×4 3

6.44

acuminata × ×veitchii 'Peter Veitch' 'Pastel Beauty' 10.12 2.13 4×6 5

acuminata × sprengeri 'Diva' 'Peachy' 10.11 2.11 4×6 5

×soulangeana (=denudata × liliiflora) 'Pickard's Firefly' 17.06 2.24 ?×? ~7.6

liliiflora 'Reflorescens' × stellata 'Rubra' 'Pinkie' 6.47 2.18 4×2 3

liliiflora × ×soulangeana 'Purple Prince 10.91 2.26 4×? ~4.8

liliiflora 'Nigra' × stellata 'Randy' 6.44 2.18 4×2 3

acuminata × 'Big Dude' (×soulangeana

'Wada’s Picture' × sprengeri 'Diva') 'Red Baron' 13.19 2.14 4×(?×6) ~6.2

liliiflora × ×veitchii 'Royal Crown' 10.58 2.20 4×6 5

liliiflora × ×veitchii 'Sayonara' 14.82 2.20 4×6 ~6.7

liliiflora × 'Mark Jury' (campbellii ‘Lanarth’ ×

sargentiana) 'Serene' 10.59 2.12 4×6 5

denudata × 'Vulcan' (campbellii 'Lanarth' ×

liliiflora) 'Shiraz' 12.76 2.19 6×5 ~5.8

liliiflora 'Nigra’ × sprengeri 'Diva' 'Spectrum' 11.58 2.18 4×6 5

campbellii × liliiflora 'Star Wars' 10.53 2.17 6×4 5

acuminata × denudata 'Sunray' 10.22 2.17 4×6 5

×brooklynensis 'Woodsman' × 'Elizabeth'

(acuminata × denudata) 'Sunsation' 14.73 2.18 4×5 ~6.8

liliiflora × stellata 'Rosea' 'Susan' 6.58 2.18 4×2 3

×soulangeana 'Lennei Alba' × ×veitchii 'Tina Durio' 15.23 2.20 ~7.6×6 ~6.9

×veitchii × ×soulangeana 'Rustica Rubra' 'Todd Gresham' 14.75 2.19 6×? ~6.7

campbellii 'Lanarth' × liliiflora hybrid 'Vulcan' 10.54 2.17 6×4 5

acuminata var. subcordata × ×soulangeana

'Alexandrina' 'Yellow Lantern' 14.43 2.18 4×5 ~6.6

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6.44

acuminata × ×veitchii 'Peter Veitch' 'Pastel Beauty' 10.12 2.13 4×6 5

acuminata × sprengeri 'Diva' 'Peachy' 10.11 2.11 4×6 5

×soulangeana (=denudata × liliiflora) 'Pickard's Firefly' 17.06 2.24 ?×? ~7.6

liliiflora 'Reflorescens' × stellata 'Rubra' 'Pinkie' 6.47 2.18 4×2 3

liliiflora × ×soulangeana 'Purple Prince 10.91 2.26 4×? ~4.8

liliiflora 'Nigra' × stellata 'Randy' 6.44 2.18 4×2 3

acuminata × 'Big Dude' (×soulangeana

'Wada’s Picture' × sprengeri 'Diva') 'Red Baron' 13.19 2.14 4×(?×6) ~6.2

liliiflora × ×veitchii 'Royal Crown' 10.58 2.20 4×6 5

liliiflora × ×veitchii 'Sayonara' 14.82 2.20 4×6 ~6.7

liliiflora × 'Mark Jury' (campbellii ‘Lanarth’ ×

sargentiana) 'Serene' 10.59 2.12 4×6 5

denudata × 'Vulcan' (campbellii 'Lanarth' ×

liliiflora) 'Shiraz' 12.76 2.19 6×5 ~5.8

liliiflora 'Nigra’ × sprengeri 'Diva' 'Spectrum' 11.58 2.18 4×6 5

campbellii × liliiflora 'Star Wars' 10.53 2.17 6×4 5

acuminata × denudata 'Sunray' 10.22 2.17 4×6 5

×brooklynensis 'Woodsman' × 'Elizabeth'

(acuminata × denudata) 'Sunsation' 14.73 2.18 4×5 ~6.8

liliiflora × stellata 'Rosea' 'Susan' 6.58 2.18 4×2 3

×soulangeana 'Lennei Alba' × ×veitchii 'Tina Durio' 15.23 2.20 ~7.6×6 ~6.9

×veitchii × ×soulangeana 'Rustica Rubra' 'Todd Gresham' 14.75 2.19 6×? ~6.7

campbellii 'Lanarth' × liliiflora hybrid 'Vulcan' 10.54 2.17 6×4 5

acuminata var. subcordata × ×soulangeana

'Alexandrina' 'Yellow Lantern' 14.43 2.18 4×5 ~6.6

acuminata × denudata 'Yellow Sea' 8.68 2.17 4×6 4

'Pegasus' (cylindrica × denudata) × campbellii

'Darjeeling' 'Zeal' 10.15 2.17 5×6 ~4.6

acuminata × figo 6.16 2.16 4×2 3

‘Galaxy' (liliiflora 'Nigra’ × sprengeri 'Diva') ×

campbellii var. Mollicomata 12.34 2.13 5×6 ~5.8

×veitchii 'Isca' × liliiflora 10.84 2.13 6×4 5

cylindrica hybrid (Polly Hill) 13.35 2.23 4×? 6.0

cylindrica hybrid (Holden via MSI seed

counter) 14.92 2.23 8×? ~6.7

cylindrica hybrid (Holden via MSI seed

counter) 15.21 2.23 8×? ~6.8

z Genome sizes were determined using 4’,6-diamidino-2-phenylindole as the flourochrome stain. Values are means of multiple

samples.

y Weighted 1CX values were calculated as: [(1CX value of the female parent × ploidy level of the female parent/2) + (1CX value of

the male parent × ploidy level of the male parent/2)]/[(ploidy level of the female parent + ploidy level of the male parent)/2] .

When the 1CX was not known for the exact parent, then an average for the parental species or section was used.

x Reported parental ploidy levels.

w Estimated ploidy levels were calculated as: 2C genome size / weighted 1CX value. If both parent species had even ploidy

levels, then ploidy levels of the progeny were rounded to the nearest whole numbers if supported by an appropriate relative

genome size. If either parent had an odd ploidy level, then ploidy levels of the progeny were rounded to the nearest 0.01 to

reflect apparent aneuploidy.

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AcknowlegementsIn addition to the co-authors of the originally published paper, I would like to thank Tom Eaker, Nathan Lynch, Joel Mowrey, Jeremy Smith, and Darren Touchell of North Carolina State University, Mills River, NC, for their technical assistance throughout the study.

Literature Cited

Azuma, H., L.B. Thien, and S. Kawano. 1999. Molecular phylogeny of Magnolia (Magnoliaceae) inferred from cpDNA sequences and evolution-ary divergence of floral scents. J. Plant Res. 112:291–306.

Azuma, H., L.B. Thien, and S. Kawano. 2000. Molecular phylogeny of Magnolia based on chloroplast DNA sequence data and floral scent chem-istry. Proc. Intl. Symp. Family Magnoliaceae 219-227.

Azuma, H., J.G. García-Franco, V. Rico-Gray, and L.B. Thien. 2001. Mo-lecular phylogeny of the Magnoliaceae: The biogeography of tropical and temperate disjunctions. Amer. J. Bot. 88:2275–2285.

Table 4. Relative genome sizes (pg) and estimated ploidy levels of artificially induced polyploid Magnolia spp.

Taxa

Relative 2C Mean

genome size (pg) z

Estimated

Ploidy level

(x)y

cylindrica 17.3 8

grandiflora ‘Little Gem’

(cytochimera) 11.11 6

21.80 12

kobus ‘Norman Gould’ 7.79 4

stellata 8.2 4

z Genome sizes were determined using 4’,6-diamidino-2-phenylindole as

the flourochrome stain. Values are means of multiple samples.

y Estimated ploidy levels were calculated as: 2C genome size / 1CX value (2.23 for M. cylindrica, 1.87 for M.

grandiflora, 2.02 for M. kobus, and 1.97 pg for M. stellata ) and rounded to the closest whole number.

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Callaway, D.J. 1994. The World of Magnolias. Portland, OR:Timber Press.

Chen, Z., X. Huang, R. Wang, and S. Chen. 2000. Chromosome data of Magnoliaceae. Proc. Intl. Symp. Family Magnoliaceae. 192-201.

Doležel, J., J. Greilhuber, and J. Suda. 2007. Flow cytometry with plant cells: Analysis of genes, chromosomes and genomes. Wiley- VCH, Wein-heim. Germany.

Figlar, R.B. and H.P. Nooteboom 2004. Notes on Magnoliaceae IV. Blumea 49:1-14.

Greilhuber, J., E.M. Temsch, and J.C.M. Loureiro. 2007. Nuclear DNA con-tent measurement, p. 67-101. In: J. Doležel, J. Greilhuber, and J. Suda (eds.). Flow cytometry with plant cells: Analysis of genes, chromosomes and ge-nomes. Wiley- VCH, Weinheim. Germany.

Jones, J.R., T.G. Ranney, N.P. Lynch, and S.L. Krebs. 2007. Ploidy levels and genome sizes of diverse species, hybrids, and cultivars of Rhododen-dron L. J. Amer. Rhododendron Soc. 61:220-227.

Kehr, A.E. 1985. Inducing polyploidy in magnolias. J. Amer. Magnolia Soc. 20:6-9.

Kim, S., C. Park, Y. Kim, and Y. Suh. 2001. Phylogenetic relationships in family Magnoliaceae inferred from NDHF sequences. Amer. J. Bot. 88:717–728.

McDaniel, J.C. 1968. Magnolia hybrids and selections. Proc. Central States For. Tree Improvement Conf. 6:6-12.

Parris, J.K., T.G. Ranney, H.T. Knap, and W.V. Baird. 2010. Ploidy Levels, Relative Genome Sizes, and Base Pair Composition in Magnolia. J. Amer. Soc. Hort. Sci., 135: 533-547.

Santamour Jr., F.S. 1970. Cytology of magnolia hybrids II. M. ×soulangiana Hybrids. Morris Arboretum Bul. 21:58-61.

Treseder, N.G. 1978. Magnolias. Boston: Faber and Faber.

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Exploring in VietnamEditor’s note: Modern-day plant explorers, Scott McMahan and Dan Hinkley, provide separate reports on their recent plant exploration trips to northern Vietnam. Dan describes the results of various sites and dates of Vietnamese ventures, while Scott focuses on their joint exploration in 2010 to the Five Finger Mountains.

Magnolias in VietnamDan Hinkley

During the past twenty-five years I have had the opportunity to examine numerous Magnolia taxa in situ: M. sargentiana, M. delavayi, M. floribunda and M. wilsoni in China, M. salicifolia and M. obovata in Japan; M. sieboldii and M. compressa in Korea; M. campbellii in Bhutan and E. Nepal. These encounters, though exciting, were only occasional incidentals to the mostly deciduous flora of each country and in no way prepared me for the opulence of the Magnoliaceous inventory of northern Vietnam.

Beginning in 1999, I have had the opportunity to visit numerous sites in Vietnam a total of seven times. Slowly but steadily, with the gracious help of Dick Figlar, I have become more comfortable in determining the iden-tity of the approximately ten species of Magnolia that occur in this region.

It should be noted that in untrammeled areas of Vietnam; i.e., with no sig-nificant deforestation, the seed of numerous Magnolias—sometimes with

their associated receptacles and sometimes not—are collected on the ground from specimens towering high overhead. Though these are often parasitized, for those that do successfully transi-tion from the collection bag through USDA in-spection to a potted plant, numerous years await before certain identification can be made.

My collections of Magnolia sp. HWJ 99461 (Hin-kley, Wynn-Jones) were made during our first as-cent of Fan Si Pan near Sa Pa in 1999. The high-est mountain in Indochina, it rises to 10,312ft, with the lower slopes seriously degraded by hu-man activity and the upper slopes an unclimac-tic monostand of bamboo. The Goldilocks zone is a dense evergreen jungle comprised chiefly of Theaceae, Lauraceae, Araliaceae, Hamamelida-ceae and, of course, Magnoliaceae.

M. grandis, a rare find in Vietnam, shown proudly by two guides

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In 1999, prior to the dedication of this area as a national park and subsequent development of basic tourist facilities, the climb up the eastern side of the mountain from the town of Sa Pa was a minimum three-day round trip. It was while approaching our first bit of forest on an upper ridge at 7,350ft that we came upon an exposed specimen of Magnolia laden with ripened seed in large, oblong, upright cones. Three of five seedlings from this collection have blossomed in my zone 8 garden, showing significant varia-tion in color, from slight pink to a handsome rose. Dick Figlar has tentatively identified them as M. insignis.

On the same mountain in 2008, but on the north-ern side outside of the park perimeter, beginning from the village of Seo Mi Ty, perennial travel-ing companions Scott McMahan and Ozzie Johnson and I, along with a legion of guides and porters, trekked along a river drainage at mod-erate elevations before climbing up onto the densely forested mountain slopes. Along this river grew a staggering diversity of Magnolias with apocarpus species (M. martini, M. foveolata and M. fulva) growing adjacent to those with cylindrical and cone-shaped fruit (respectively, M. cathcartii and M. insignis; M. sapaensis and M. grandis). Finding the latter is considered to be a new record for Vietnam, as it has been known only to southern Yunnan prior to this.

Besides the Magnolias, also present of note were Acer, Styrax, Illicium, Mahonia, Edgeworthia and Stauntonia.

In 2006, 2008 and 2010 we traveled to the north-west of Lao Cai to an area of moderate eleva-tion on the Chinese frontier known as Y Ty. At-testing to how close to the border we actually were on our last trip, our campsite was visited the first night by border police, who spent con-siderable time perusing our passports. This is

Rusty indumentum on underside of M. foveolata leaves.

Magnolia aff. insignis HWJ 99621

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a remarkable area with a rich aggregation of familiar genera, including Acer, Rhodoleia, Loropetalum, Schefflera and Magnolia, though the local tribal minorities are still cutting the forests for firewood at an alarming rate.

Most memorable here were stunning specimens of M. foveolata, with leaves undersurfaced in a rich rusty red indumentum. Fortunately, we were afforded the luxury of youthful and agile porters who would readily scale the trees barefoot to help collect seed.

There are remarkable changes happening in Vietnam, in regard to its en-vironmental ethos as well as the ex-istence of tourist facilities through-out much of the country. In addi-tion to its lovely and welcoming people and French-infused cuisine, there exists a superb inventory of plants readily witnessed if but with a bit of physical exertion.

Exploring in Five Finger Mountains, VietnamScott McMahan

Last fall, I had the opportu-nity to travel back to the high mountains of northern Viet-nam with my faithful traveling companions, Ozzie Johnson and Dan Hinkley. This was the second time we had botanized in these mountains together. Our main goal was to continue to try to explore remote areas in the Fan Xi Pan mountain

A specimen of M. sapaensis illustrates the unique attributes of this species: coppery-golden pubescence on the buds only, and the rich green leaves are contrasted by glaucous-white on their backsides.

A view of the Five Finger Mountains

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range as well as do some snooping around in a new area or two in order to begin to test the hardiness of these Vietnamese plants in gardens both in the southeast as well as the Pacific Northwest.

Outside of the Fan Xi Pan Mountains, one of the most interesting areas for temperate flora we explored was a group of mountains called the Five Finger Mountains. Hiking in this part of the world could almost be in-terchanged with the word ‘mountaineering’. The mountains that create the border between China and Vietnam are rugged, steep jungles that are difficult at best to navigate, and hacking through them is the only way to make progress.

This part of the trek began with our driver dropping us off at a turn in the road where the three of us, our trusted guides, Uoc and Ton, and three porters piled out. Since there are no real roads leading up into the moun-tains, other than rutted out pig trails used by motorbikes, our adventures in this region usually begin in this way. We started out by climbing up into the mountains on a dirt path that wound through some sort of a work camp and finally into the jungle. Along the way, we began to notice the change from cut-back trees and shrubs that were struggling to grow along the trail to majestic, broad-leaved evergreen tree outcroppings, which led the way to the dense canopy in the mountains. I began to realize that these huge trees in the distance were not oaks or maples such as we had seen at lower elevations…they were at least three different species of ma-ture magnolias. What a feeling to be standing amongst groves of Asian magnolias that had been allowed to grow and mature!

Our main method of germplasm collection is via seed. While most of the magnolias were not laden with ripe cones full of seed, we did make sev-eral significant collections in this area and were able to tentatively identify those species, thanks to Dick Figlar and digital photography. I began snapping photos and collecting not only seed, but also branch cuttings, which I could clearly photograph later and send to Dick. Before I left for my trip, I had received an in-depth tutorial on keying out evergreen species of magnolias from Dick in his garden. Because of this exercise, I was able to give him descriptive information about the buds, undersides of the foliage, glossiness of the leaf, the presence or absence of leaf scars, and other

Fellow plant explorer Dan Hinkley walking toward groves of M. foveolata growing in a moist valley in the Five Finger Mountains.

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details. By exchanging emails and pictures, we usually had valid identifi-cation for our collections within 24 hours.

In the areas we visited on this trip, Magnolia foveolata seemed to be the most widespread. We usually found this species growing in full sun, but the

soil conditions ranged from fairly dry pastures to very wet, bog-like conditions. I would never have imagined that these huge trees would have grown so well with their roots completely submerged in water. The trees themselves were as diverse as the conditions they grew in. Some had beautiful golden indumentum on the un-dersides and some displayed fine silver hairs and some had none at all. Based on foliage alone, very ornamental selections of this har-dy species could be made.

As we continued onward up into the mountains, we came across an im-pressive Magnolia species growing happily by a river. Characterized by long, narrow leaves with short stipule scars along with prominent flower buds covered in golden indumentum held in the leaf axils, we wondered if it was M. floribunda. As far as we could tell, this was one of the only specimens of this particular taxon we encountered. Growing close by, we also found quite a few specimens of M. insignis, which has a wide natu-ral distribution, from northeast India, Nepal and southern Sichuan in the north to northern Vietnam and Thailand in the south. While there are several hardy selections of M. insignis being grown in the US, M. insignis from this area unfortunately seem to be very tender. I was especially dis-appointed with the apparent lack of hardiness of M. insignis, as collections from previous trips to this region have yielded vigorous plants with hints of red pigment in the foliage, but north Georgia winters (zone 7) have proven to be too cold for them.

At our highest elevation of Magnolia collection from this area (6,700ft), we discovered a very exciting and rare species known as Magnolia cathcartii. We had seen this species at lower elevations without fruit and while it did resemble something in Magnoliaceae, I decided that it more closely re-sembled something related to Ficus and continued on. Compared to other Magnolias in the area, this species has very small, glossy foliage complete-ly free of indumentum. When we finally came upon a tree with fruit on it and could then positively identify it as a Magnolia, we collected the seed

M. foveolata with ripe seed

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and began taking pictures to send to Dick, hoping for quick identification. Little did I know, this species is easily identified by a very prominent mid-rib on the upper surface of the leaf. What a great find as this species is virtually non-existent in US gardens.

I have now seen with my own eyes the amazing diversity of Magnoliaceae that occurs from southwestern China and into the mountains of northern Vietnam. In fact, of the six collecting trips I have made to Western China and Northern Vietnam, the trip we took in the fall of 2010 proved to me that much exploration still needs to be done in the mountains that create the border between these two countries.

I would like to thank my friends Dick Figlar and Philippe de Spoelberch for their very generous support of my collecting efforts last fall. Without these sorts of collaborations with individuals, botanical institutions and serious plant societies, explorations and plant introductions of this sort would be impossible.

Glossy M. cathcartii leaves with prominent mid-rib

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New cultivar registrations 2010-2011Timothy M. Boland, Registrar, Magnolia Society InternationalExecutive Director, Polly Hill Arboretum

The following two cultivars were submitted by William Forster, Denni-son, Illinois, USA. Both trees grow just west of Charleston, Illinois (USDA zone 5b), in black prairie loam soil. Selected, named, and cultivated by Wesley Whiteside who received seeds from the late J.C. McDaniel of Champaign-Urbana, Illinois. The seed parent was Magnolia ×brooklynen-sis ‘Woodsman’; the pollen parent is unknown. The following two trees described below were selected out of a dozen seedlings that resulted from this cross. These magnolias prefer full sun and moisture-retentive soils.

‘Illini Gold’ (Magnolia xbrooklynensis ‘Woodsman’ x unknown taxon)The tree is described as a vig-orous grower and at 26 years of age is estimated to have a height of 35ft (10.6m) and a width of 15ft (4.5m). The flowers were first observed in 1995 and are described as an excellent yellow and pro-duced in large amounts. Typi-cal bloom time is late April in southern Illinois. The tree shape and flowers are very similar to M. acuminata.

‘Illini Moonlight’ (Magnolia xbrooklynensis ‘Woodsman’ x unknown taxon)The tree is described as a vig-orous grower and at 26 years of age is estimated to have a height of 35ft (10.6m) and a width of 15ft (4.5m). The flowers were first observed in 1995 and are described as medium yellow and smaller in size compared to ‘Illini Gold’. Typically in bloom in late April in southern Illinois, tree shape and flowers are very similar to M. acuminata.

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Both trees are available from:

Whitman Farms3995 Gibson Road, NWSalem, Oregon, 97304 http://whitmanfarms.com

Magnolia StorePiet Vergeldt Boomkwekerij bvHorsterdijk 1035973 PM Lottum The Netherlandshttp://www.magnoliastore.com

Registered by William Forster, Dennison, Illinois, USA

‘Simpson’s Hardy’ (Magnolia grandiflora)This tree has grown for over 60 years at the Simpson Nursery Company, Vincennes, Indiana, USA (USDA, zone 6a). It was originally purchased from an unknown source. Robert Simpson, the original proprietor of the nursery, had planted it as a Mother’s Day gift. The tree is considered unique for its hardiness, surviving -30°F (-34°C). It is described as pyra-midal when grown in full sun, producing large white flowers 12in (30cm) in diameter. The foliage is heavy, dark green with good indumentum. At present time the tree is 65ft (20m) in height and 30ft (9m) in width. The tree has carried the unofficial name of ‘Simpson’ for a few years and was previously mentioned under this name in this journal, Issue 60, Summer 1996. However, accord-ing to Betsy Simpson, daughter of the late Robert Simpson, and current proprietor of the Simp-son Nursery Company, they have always referred to it as ‘Simpson

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Hardy’ or ‘Simpson’s Hardy’. The current registration of this name at-tempts to stabilize its use in the nursery trade and capture the unique cold tolerance of this primarily southern species. It is recommended that the tree be purchased on its own roots to insure a hardy constitution, or at the very least, be grafted on rootstock known to be hardy in northern climates.

The tree is available from:

The Simpson Nursery Company1504 Wheatland Rd PO Box 1216Vincennes, IN 47591info@simpsonnursery.com

Rare Find Nursery957 Patterson RoadJackson, NJ 08527rarefindnursery.comsupport@rarefindnursery.com

Pleasant Run NurseryPO Box 247Allentown, NJ 08501http://www.pleasantrunnursery.compleasantrunnursery@verizon.net

Registered by William Forster, Dennison, Illinois, USA, on behalf of Betsy Simpson.

‘After Elizabeth’ (Magnolia hybrid origin)Selected and named by Tom Krenitsky of Chapel Hill, North Carolina, USA. The tree was raised as a seedling of unknown progeny. First observed in the spring of 1990, it exhibits flowers similar to Magnolia ×soulangeana but with distinct markings (pur-plish-red) on the outer tepals. Magnolia expert Richard Fi-glar has suggested that it may be a backcross of Magnolia lili-iflora with M. ×soulangeana. It flowers prolifically and over a

Original tree located at Simpson Nursery, Vincennes, Indiana, USA

(photo by Sylvia Stanat)

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three-week period. The originator noted its late March bloom (after frosts) as a positive attribute. It always followed the bloom of Magnolia

‘Elizabeth’ in his gar-den; thus, he decided upon the name des-ignated here. Subse-quently, it has been propagated by Camellia Forest Nursery in Chapel Hill, NC, and report-edly roots easily under mist and grows well in containerized production. The tree can be grown as a multi-stem or single stem tree in production. Currently, the original tree is 20ft. (6m) tall and has multiple trunks. The tree has been distributed in Europe in recent years and is available in the USA from:

Camellia Forest Nursery620 Hwy 54 WestChapel Hill, NC 27516http://www.camforest.com/CamelliaForest@gmail.com

Registered by Tom Krenitsky of Chapel Hill, North Carolina, USA

(photo by Sylvia Stanat)

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Specialists in full-standard Magnolias

MASETTI S A BI N ON U R S E R I E S

S.S.A.

w w w w.v ivaimasett i sabino. i t

Via bassa della Vergine, 214/C - 51100 Pistoia - ItalyTel. +39 0573 380404 - Fax +39 0573 985028

info@vivaimasettisabino.itwww.vivaimasettisabino.it

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The Research Foundation of the Magnolia SocietyThe Magnolia Society Endowment Fund needs your support

Please send your contributions to:The Research Foundation Fund

518 Parker StreetGibson, TN 38338 USA

Contributions are tax deductible in the United States.

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We offer more than 450 varieties of grafted magnolias.

Among these are some of the latest

hybrids and very rare selections of Magnolia species.

Full stock list and availability as download or on request.

Worldwide shipping – international orders welcome.

Visit our reworked website with many magnolia photos!

EISENHUT NURSERIES CH 6575 San Nazzaro Switzerland Tel: +41 91 795 18 67 Fax: +41 91 795 30 29 Internet: www.eisenhut.ch e-mail: info@eisenhut.ch

Container grown on their own roots 80 + varieties Mail Order available

National collections of Deciduous Azaleas NURSERY OPEN BY APPOINTMENT ONLY

THE OLD LODGE, ISAACS LANE

HAYWARDS HEATH, WEST SUSSEX RH16 4SA TEL/FAX 01444 458084

www.heaselandsnursery.co.uk

HEASELANDSGARDENNURSERYSpecialist growers ofHardy Hybrid Rhododendrons

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Broken Arrow Nursery13 Broken Arrow Rd. Hamden, CT 06518

Growers of more than 50 different magnolias as well as countless other rare and unusual plants

www.brokenarrownursery.comRetail • Mail-order • Wholesaleinfo@brokenarrownursery.com

203.288.1026

Magnolia x ‘Daybreak’

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Magnolia Society International, Inc.

Officers

PresidentAndrew Bunting408 Vassar AvenueSwarthmore, PA 19081abuntin1@swarthmore.edu

Vice President Gary KnoxUniversity of FloridaN. Florida Research and Education Center155 Research Rd.Quincy, FL 32351

SecretaryBeth Edward3000 Henneberry RoadJamesville, NY 13078

TreasurerLarry Langford518 Parker StreetGibson, TN 38338

EditorCheryl Doyle Kearns102 Colonial DriveYoungsville, NC 27596cherylkea1017@yahoo.com

Acting WebmasterBeth Edward

Standing Committee Chairs

Registered Corporate AgentKaren Vallowe

Finance Larry Langford

ResearchDr. Paul Cappiello

Annual Meetings ChairAnita Figlar

International Registrar of Magnolia CultivarsTimothy M. Bolandtim@pollyhillarboretum.org

NominationsGary Knox

Seed CounterStefan P. Cover

Awards and HonorsRichard B. Figlar