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)
prostrate
acaulescent
caulescent
cespitose
repent
arborescent
suffrutescent
decumbent
Stem Branching Pattern
sympodial
monopodial
dichotomous
sympodial
Twig Structure
collateral
pseudoterminal
naked
superposed
infrapetiolar
Leaf Structural Type
bractlets
bract
phyllode
scale
spine
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
Iris sp.
unifacial
Seismonasty
Mimosa pudica Fabaceae
Leaf Type / Parts
imparipinnate
simple
pinnately
compound
paripinnate
bipinnately
compound
Leaf Type / Parts
palmate-ternate
pinnate-ternate
ternately compound
= trifoliolate
biternately
compound
palmately
compound
Leaf Type / Parts
geminate
unifoliolate
bigeminate
geminate-pinnate
costa-palmate
petiolate
sessile
sheathing
decurrent amplexicaul
perfoliate
connateperfoliate
Leaf Venation
Leaf Venation