Vocabulary Definitions

 LEAVES

Retention
deciduous - shed annually at the end of the growing season
persistent (evergreen) - remaining attached one to several years

Attachment

Parts and Types

blade - the flat, expanded portion of a leaf
leaflet - a portion of a leaf blade that is subdivided into several smaller blades
margin - edge of the leaf
simple - not compound, having a single blade
compound - composed of 2 or more similar leaflets attached to a rachis
petiole - stem of a leaf
stipule - a leaflike appendage of the base of the petiole, usually one on each side of the petiole
palmately compound - a leaf composed of several leaflets radially diverging from the petiole like the spread of fingers on a hand
pinnately compound - a leaf composed of several leaflets arranged on each side of a common rachis

Shapes

needle - long and very narrow, circular in cross-section (needle-shaped
awl-shaped - broad at the base tapering to a sharp point at the ape
cordate - heart-shape
lanceolate - lance-shaped, several times longer than wide, with the broad end basal
linear - long and narrow, with parallel edges
oblanceolate - lance-shaped with the broad end distal
scale - small, flattened (like fish scales)
ovate - shaped like the longitudinal section of an egg, with the broad end basal
elliptical - oval, with the form of an ellipse, rounded about equally at both ends

Leaf Margins and Tips

entire - leaf margins without divisions, lobes or teeth
lobed - leaf margins with elongated pointed or rounded extensions
revolute - leaf margins rolled to underside
serrate - leaf margins toothed, teeth pointing upward or forward
acuminate - lleaf tip gradually tapering to the apex, long pointed
acute - leaf tip sharply pointed, but not drawn out
notched - leaf tip indented at the apex
obtuse - leaf tip blunt or rounded at the apex
truncate - leaf tip ending abruptly, as if cut off at end

Leaf veins 

arcuate - leaf veins curved toward apex
palmate - veins arising from one point
pinnate - veins arising from each side of a common axis
parallel - having the main veins extending through the leaf longitudinally and in parallel arrangement

Surfaces
glabrous - smooth without hairs
glaucous - white, waxy covering
pubescent - with fine hairs

Other Terms
bract - leaflike structure (modified leaf), provides a function other than for photosynthesis
node - point from which a leaf or branch emerges on a stem
petiolate - leaf attachment with a petiole
sessile - leaf attachment without a petiole

 FLOWERS

Definition: The reproductive structure of Angiosperms containing stamens and/or pistils (with or without other parts, see below)

Basic terms 
dioecious - unisexual, the staminate and pistillate flowers on different individuals
monoecious - bisexual, the stamens and pistils in separate flowers but borne on the same individual
complete - flowers having sepals, petals and the two vital reproductive parts--the pollen producing stamens (male) and the pistils (female) with basal ovary enclosing ovules
incomplete - flowers lacking one or more of these four parts
imperfect - unisexual flowers have either stamens or pistils but not both
perfect - flowers having both stamens and pistils, sepals and petals may or may not be present

Inflorescence - a dense group of flowers on a stem

ament, or catkin - a scaly bracted spike of usually unisexual flowers, frequently deciduous in one piece
cyme - a flat-topped loose flower cluster, flowers with stalks
head - a dense, flat or round inflorescence; flowers without stalks
panicle - a compound raceme
spike - a simple inflorescence of sessile flowers arranged on a common, elongated axis
raceme - a simple inflorescence of stalked flowers on a more or less elongated axis

Parts

anther - the pollen-bearing part of the stamen
calyx - all of the leaflike bracts subtending the corolla
corolla - all of the petals
filament - the stalk of the anther
ovary - the part of the pistil that contains the ovules
ovule - seed before fertilization
perianth - calyx plus corolla
petal - a division of the corolla or inner part of the perianth, typically colorful to attract pollinators
pistil - female organ of a flower, consisting of ovary, style and stigma
sepal - a division of the calyx, usually bract-like
stamen - the pollen-bearing (male) organ of the flower
stigma - the part of a pistil that receives pollen for fertilization of the ovules
style - narrow upward extension of the pistil between the ovary and the stigma

SEED-BEARING STRUCTURES

Seeds - the completely matured and modified ovule containing an embryo
Gymnosperms - plants bearing naked seeds (simple wood composed mainly of tracheids)
 aril - a seed partially enclosed by red, fleshy covering
cone - female, large structure with seeds on overlapping scales; male, small structure with pollen sacs
Angiosperms - plants with seeds in an ovary (complex wood composed mainly of vessels and fibers)

FRUITS: Mature ovary containing seeds

TWIGS

bud - the undeveloped state of a shoot, with or without scales
bud scale - hardened scale-like structures covering buds
cambium - layer of dividing cells beneath the bark, increases stem diameter
cruciform buds - 3 buds fused in the shape of a cross
imbricate scales - overlapping like shingles
lateral bud - along twigs, typically in axils of leaves
leaf scar - scar left on a twig by the abscission of a leaf
terminal bud - at apex of a twig
pith - the central softer part of a stem
shoot - a unit of vegetative growth; including twigs, buds and leaves
spine, thorn - a sharp, mostly woody outgrowth in the position of a leaf or stipule
sterigmata - small woody, peg-like projections to which leaves are attached
lenticel - a corky growth on young bark that admits air to the interior of a twig or branch

Tree Form