Plant Classification & Identification

Junior High Agriculture

Life Cycle

Annual – completes life in one growing season Stages - germination, growth,

flowering, death Examples – marigolds, corn,

soybeans, impatiens, zinnias, wheat

Life Cycle

Biennial – completes life in two growing seasons Stages - germination, growth,

dormancy, growth (season 2), flowering, death

Examples – musk thistle, cabbage, primrose

Life Cycle

Perennial – will live for more than two growing seasons Stages - germination, growth,

flowering, dormancy, growth, flowering, etc.

May be woody or herbaceous Examples – Kentucky bluegrass, bur

oak, alfalfa, lilac, white clover

Growth Habit

Trees – woody perennials with a single, erect trunk

Shrubs – Woody perennials with more than one main trunk

Cacti – Perennials with spines and green fleshy stems

Growth Habit

Grasses – plants with jointed, round hollow stems, and parallel veins in leaves

Grass-likes – look similar to grasses without joints, triangular or round stems

Forbs – herbaceous broadleaf plants generally netlike veins in leaves

Foliage Retention

Deciduous – lose all leaves in autumn

Evergreen – retain leaves and remain green throughout the year Drop leaves throughout year, just not all at

once Broad-leaf or Needle-leaf

Leaf Characteristics Five common characteristics of leaves used

for identification Leaf arrangement on the stem Leaf venation pattern Complexity of the leaf Leaf shape Leaf surface

Arrangement on Stem Alternate – only 1 leaf per node

Opposite – 2 leaves per node

Whorled – 3 or more leaves per node

Venation Pattern Parallel – major veins run the length of the leaf,

parallel to the midrib, veins are about equal in size, found in grasses and grass-likes

Pinnate – have one major vein, with secondary veins branching from the midrib, found in trees, shrubs, and forbs

Palmate – have three or more major veins extending from the base of the blade and secondary veins branching from the main veins, found in trees, shrubs, and forbs

Venation Pattern

Parallel PinnatePalmate

Leaf Complexity Simple – only 1 blade

Compound – several leaflets attached to a common leaf stalk Palmately divided – all leaflets branching

from 1 point Pinnately divided – leaflets arranged along

both sides of the leaf stalk (Even or Odd) Twice or Bi-pinnately divided – leaf stalk has 2

or more branches from main stalk

Leaf Complexity

PalmateSimple

Even Pinnate Odd PinnateTwice Pinnate

Leaf Shapes Cordate – heart-shaped

Deltoid – triangular shaped

Elliptical – broad in middle, tapers at both ends

Lanceolate – narrow with widest point at base

Linear – much longer than wide, sides parallel

Ovate – wide and broad at the base

Leaf Shapes

Lanceolate LinearOvate

Cordate DeltoidElliptical

Leaf Margins Crenate – broad, round teeth with narrow, open

spaces between them

Dentate – sharp teeth pointing outward

Entire – margin is smooth with no teeth or indentations

Lobed – indentations from ¼ to all of the way to the midrib

Serrate – saw-like teeth that are pointed forward

Leaf Margins

LobedSerrate

Crenate DentateEntire

Leaf Surface Glabrous – surface is free of hairs

Glandular – surface has small glands which secrete resin

Hirsute – stiff hairs cover the surface

Pubescent – soft, short hairs cover the leaf surface

Scabrous – surface is rough to the touch, similar to sandpaper

Inflorescence Types The flower inflorescence is the arrangement of the

flowers on the stem. A few common types are: Corymb – short, broad, flat-topped Head – dense cluster of stalkless flowers Panicle – flowers developing toward the tips of the

branches as the elongate Raceme – flowers arranged along a main axis on

short stems Spadix – very small flowers massed together,

enclosed in a spathe Spike – flowers along a single axis Umbel – flat-topped cluster of flower, no central axis

Inflorescence Types

Corymb HeadPanicle Raceme

Inflorescence Types

Spadix SpikeUmbel

Tree Fruits Drupe – fleshy with a single stone or pit (cherry)

Berry – fleshy with several seeds (persimmon)

Pome – fleshy outer coat and stony layer and several seeds within (apple, pear)

Legume – dry, elongated pod that splits in two with several seeds along one edge (honeylocust)

Capsule – dry fruit that splits to reveal many seeds inside (catalpa)

Tree Fruits Achene – small, dry, and hard one seeded fruit,

often tightly packed together with hundreds of fruits (sycamore)

Samara – one or two flat wings attached to a seed (maple)

Nut – hard, with an outer husk that does not split open readily and an inner papery to woody shell (black walnut)

Acorn – nut-like fruit of an oak, with a scaly or warty cap

Tree Fruits

LegumeCapsule

Drupe BerryPome

Tree Fruits

NutAcorn

AcheneSamara