Plant Morphology

Michael G. Simpson

Plant Structure Terms

Used for a specific structure/organ

Plant Habit= general form of a plant, encompassing stem duration and

branching pattern, development, or texture.

Herb - plant with annual above-ground parts

Geophyte - perennial herb with rootstock

Vine - weak stemmed

Liana - woody vine

Shrub - woody, multiple stems from base

Subshrub - woody just above ground

Tree - woody, one trunk

Plant Duration= how long a plant lives.

Annual- ≤ 1 year

Biennial- 2 years

Perennial- 3 or more years

Plant Habitat= environment where plant lives.

Terrestrial

Aquatic

Submersed

Floating

Emergent

Epiphytic

Saxicolous

Plant Life Form= structure, life cycle, physiology.

Therophyte – annual

Geophyte – perennial herb

Epiphyte – plant growing on another plant

Halophyte – salt-adapted plants

Succulent – plant with fleshy leaves or stems

Xerophyte – plant living in dry, hot environments

Roots

Function - absorption, anchorage

Structure - rootcap, root hairs, endodermis

Adventitious roots - arise from non-root organ

Lateral roots - arise from another root (1˚, 2˚, etc.)

Root Types/Parts

taproot fibrous prop haustorial

Root Types/Parts

storage roots Raphanus sativus, radish

Root Types/Parts

buttress roots Ficus rubiginosa, rusty-leaved fig

Root Types/Parts

pneumatophores Avicennia germinans, black mangrove

Root Types/Parts

prop roots (also adventitious)

Shoot

= stem + associated leaves

Each leaf primordium develops into one leaf.

Caryota sp. Arecaceae

ca. 20 feet long!

Stem (Shoot) Types

areole bulb caudex caudiciform stem

Stem (Shoot) Types

cladode corm culm fascicle/short shoot

rhizome

Stem (Shoot) Types

scape stolon/runner thorn tiller tendril tuber

Stem (Shoot) Types

pachycaul pseudobulb

Stem Habit=relative position of stem (+ growth, structure)

acaulescent caulescent cespitose

prostrate

repent

arborescent suffrutescent decumbent

Stem Branching Pattern

monopodial dichotomous

sympodial

sympodial

Twig Structure

collateral superposed

pseudoterminal naked infrapetiolar

Leaf Structural Type

bractbractlets

scale

phyllodespine tendril (leaf) unifacial leaf

Leaf Structural Type

Bract (flower) Epicalyx Bud Scale

Leaf Structural Type

Phyllode - Acacia spp. (Fabaceae)

Leaf Structural Type

Tendril - Lathyrus (Fabaceae)

Leaf Structural Type

Stipular Spine - Euphorbia spp. (Euphorbiaceae)

Leaf Structural Type

Petiolar Spine - Fouquieria splendens Ocotillo (Fouquieriaceae)

Leaf Structural Type

Leaf Spine (arising from areole) - Cactaceae

Sharp things

thorn - sharp-pointed stem/shoot (fr. axillary bud)

spine - sharp-pointed leaf or leaf part leaf spine (also leaflet spine) stipular spine petiolar spine

prickle - sharp pointed epidermal appendage

Leaf Structural Type

Pitcher Leaf - Nepenthes (Nepenthac.) Sarracenia (Sarraceniac.)

Leaf Structural Type

Tentacular Leaf - Drosera spp Sundew (Droseraceae)

Leaf Structural Type

Trap Leaf - Dionaea muscipula Venus Fly Trap (Droseraceae)

Leaf Structural Type

Dionaea muscipula Venus Fly Trap (Droseraceae)

Leaf Structural Type

unifacial

Iris sp.

Seismonasty

Mimosa pudica Fabaceae

Leaf Type / Parts

simple pinnatelycompound

imparipinnate

paripinnate bipinnatelycompound

Leaf Type / Parts

ternately compound= trifoliolate

palmate-ternate pinnate-ternate biternately compound

palmatelycompound

Leaf Type / Parts

unifoliolate

geminate

bigeminate geminate-pinnate costa-palmate

petiolate sessile sheathing decurrent amplexicaul perfoliate connate-perfoliate

Leaf Venation

Leaf Venation