achene: a small, one-seeded fruit which does not split open
aggregated fruit: a fruit formed from a cluster of ovaries from a single flower, like a blackberry.
alternate: one leaf at a leaf node.
annual: completion of a life cycle in one year.
anther: the sac on a stamen where pollen is produced.
anthocyanin: a purplish or reddish, water-soluble, glycoside pigment
banner: the upper petal of a flower in the pea family
basal: at the base of a plant
berry: a fruit with a fleshy ovary wall and more than one seed, like a tomato.
biennial: completion of a life cycle in two years.
bilateral: having two sides.
bipinnate: twice pinnate with primary and secondary divisions.
bract: a much reduced or modified leaf subtending a flower or inflorescence.
calyx: the first outer parts of the perianth of a flower; the collection of sepals.
capsule: a dry fruit from a compound ovary that cracks open when dry.
catkin: a unisexual, spike-like, pendulous inflorescence of flowers lacking petals.
clasping: a sessile leaf that partly surrounds the stem.
composite: made up of distinct parts.
compound inflorescence: an inflorescence that is branched.
compound leaf: a leaf that is divided into leaflets.
compound umbel: an umbel that is branched into successive umbels, like that of a carrot.
cone: a compact strobilus of ovule-bearing or pollen-bearing bracts, found on gymnosperms.
conifer: a cone-bearing plant; a plant in the order Coniferales.
cordate: heart-shaped.
corolla: the second outer parts of the perianth of a flower; the collection of petals.
corymb: a flat-toped inflorescence due to different length pedicels; the outer flowers mature first.
cuspidate: tipped with a short, sharp, abrupt, rigid point.
cyme: a flower cluster in which the center or terminal flower blooms first.
deciduous: falling away, such as leaves that fall from a tree at the end of a growing season.
decurrent: extending downward, usually along a stem.
dicot: a flowering plant with two seed leaves.
dimorphic: in two forms.
dioecious: male (staminate) and female (pistillate) flowers borne on separate plants.
disk flowers: tubular flowers that make up the central disk of composite flowers in the Asteraceae.
distichous: in two vertical rows, usually applied to leaves.
drupe: a fleshy fruit with a stony inner part that surrounds the seed, like a peach.
drupelet: a minute drupe that part of an aggregate fruit.
floret: a small flower in a cluster; a grass flower.
fruit: a ripened ovary and associated structures.
gall: a swelling of plant tissue caused by a parasite.
glabrous: without hairs.
glaucous: covered with a whitish or bluish waxy coating.
glume: one of the empty bracts below a grass spikelet (the grass inflorescence).
gymnosperm: a vascular plant with seeds not enclosed in an ovary (the group name “Gymnospermae” from Greek means “naked seeds”).
halophyte: a plant that grows in salty soil.
hastate: arrowhead-shaped but with the basal lobes pointing sideways instead of backward.
haustorium (pl. haustoria): an absorptive structure of a parasite that penetrates cells of a host to derive food.
head: a dense collection of sessile or nearly sessile flowers making up an inflorescence.
herb: a plant with non-woody parts that are above the ground.
heterotrope: an organism that obtains its food from external sources.
hirsute: hairy.
hispid: hairy with stiff, sharply pointed bristles.
inferior ovary: ovary below the petals, sepals and stamens.
inflorescence: arrangement of flowers on a plant.
invasive: a non-native plant that has become a pest.
involucre: a whorl of bracts that subtends a flower or inflorescence.
irregular flower: a flower that is not radially symmetrical; synonymous with “zygomorphic flower”.
keel: a ridge like the keel of a boat; the two partly-united, lower petals of a flower in the pea family.
lanceolate: lance shaped, much longer than wide.
leaf axil: the angle between the leaf and stem; some flower originate from the leaf axil.
leaflet: the leaf-like division of a compound leaf.
legume: a member of the pea family, the Fabaceae, formerly the Leguminosae.
lemma: the lower and larger of two bracts enclosing a grass flower.
lip: the upper or lower petal or sepal of an irregular flower; it is often expanded.
ligule: membranous tissue in grass projecting upward between the leaf and the stem.
lobe: a separate, often rounded, division of a plant part such as a leaf or petal.
locule: a compartment of an ovary.
midrib: the central rib of a leaf.
monocot: a flowering plant with one seed leaf.
monoecious: male (staminate) and female (pistillate) flowers borne on the same plant.
mycorrhizae: a symbiotic combination of fungi hyphae (individual fungal cells) and the roots of seed plants.
node: the place on a stem where a leaf attaches.
notch: a v-shaped indentation; compare with serrate in which the teeth of the notches are pointed forward.
oblanceolate: lance-shaped but with the broad part above the middle and the taper toward the base; an oblanceolate leaf would have the longer taper toward the petiole.
obovate: inversely ovate with the longer taper toward the base.
ocrea (pl. ocreae): sheath around a stem formed by leaf stipules; found in the buckwheat family, the Polygonaceae.
opposite: paired structures directly across from each other, as with leaves at the same node.
ovary: the basal, seed-bearing part of the pistil.
ovate: egg-shaped with the longer taper toward the apex and the broader dimension near the base.
ovule: an immature seed.
palea: the inner and smaller of the two bracts enclosing a grass flower (floret).
palmate: spreading from a common point, like the fingers from the palm of a hand.
panicle: a compound inflorescence arranged along a central axis on which the lower flowers open first.
pappus: a crown of bristles on the achene of the disk flower in the Asteraceae, used for seed dispersal; the “down of a thistle”.
parasitic: deriving nutrition from the living tissues of another the organism; in botany, a plant not capable of making food for itself and living off another organism.
parasitoid: a wasp that completes larval development within the body of another insect, in this case the larvae of Diplolepis.
parenchyma: tissue composed of living, thin-walled cells that are randomly arranged. In a leaf, the tissue between the upper and lower epidermis.
pedicel: stalk of a single flower (see peduncle).
peduncle: stalk of an inflorescence (flower cluster), or the stalk of a solitary flower (see pedicel).
pendent: hanging or drooping.
perennial: persistent annual cycles, the plant completing an annual life cycles year after year.
perfect flower: a flower with both stamens and pistils; male and female parts in the same flower.
perianth: collectively, the petals and sepals; the corolla-calyx complex.
petal: a unit of the corolla.
petiole: the stalk of a leaf or compound leaf.
phyllary: one of the bracts that subtends the composite flower of the Asteraceae.
pinnate: arranged along opposite sides of an axis; a compound leaf with leaflets arranged in this manner.
pistil: the seed-producing (female) organ of a flower consisting of the stigma, style, and ovary.
pistilate: a flower with pistils only, no stamens.
pod: a dry fruit that releases its seeds by splitting open when it is mature; a legume.
prostrate: referring to a stem that lies flat on the ground.
pubescent: covered with soft, short hairs.
pupa: the stage of insect metamorphosis between larva and adult.
raceme: an inflorescence where pediceled flowers are attached to an elongated axis; younger flowers are near the apex.
rachis: an extension of the petiole of a compound leaf that bears the leaflets. The main axis of a compound leaf. (In zoology, the center shaft of a feather.)
ray flower: an outer, strap-shaped flower of a composite head of the Asteraceae.
receptacle: the part of a flower that bears the flower organs; the end of a pedicel or peduncle to which the flower is attached (syn. torus).
regular flower: a flower that is radially symmetrical; synonymous with “actinomorphic flower”.
reniform: kidney shaped.
retuse: a rounded apex with a shallow notch at its center; a leaf with a shallow notch in its otherwise rounded end.
rhizomatous: having rhizomes.
rhizome: a perennial, prostrate, underground stem, usually rooting at nodes and sending up shoots.
riparian: living near a lake, stream, or river.
rosette: arranged in a circular fashion; usually a circular cluster of leaves at the base of a plant.
runner: a slender, horizontal, stolon-like stem that roots from its apex, like those of a strawberry plant.
samara: a dry, indehiscent winged fruit such as found on a maple or ash.
sclerenchyma: long, thick-walled (lignified), supportive cells associated with vascular bundles; they form sclerenchyma fibers.
sepal: one of the units of the calyx.
septum: a partition between cavities.
serrate: having sharp teeth directed forward; saw toothed.
serrulate (also serratulate): serrate with small teeth.
sessile: without a stalk or stem.
sheath: a tubular envelope around a stem.
shrub: a perennial, woody plant without a distinct trunk, considered shorter than a tree.
silicle: a fruit that separates lengthwise, the halves not much longer than wide; in the Brassicaceae (see silique).
silique: a fruit that separates lengthwise, the halves much longer than wide; in the Brassicaceae (see silicle).
simple: undivided or unbranched.
sinuate: wavy.
spadix: a spike with a fleshy axis.
spathe: a large bract enclosing an inflorescence.
spatulate: spatula-shaped; broad and rounded at the apex and tapering toward the base.
spike: an inflorescence with sessile flowers on a long axial stem, the lower flowers blooming first.
spikelet: an aggregation of florets in grasses; a secondary spike.
sporangium (pl. sporangia): a structure that produces asexual spores.
sporangiophore: a structure that bears sporangia.
spur: a hollow projection from a petal or sepal that secretes nectar.
stamen: the pollen-producing (male) organ of a flower consisting of the filament and anther.
staminate: a flower with stamens only, no pistils.
sterile: infertile or barren.
stigma: the sticky tip of the pistil, the female organ of the flower, that traps pollen.
stipule: one of a pair of projections at the base of a petiole; it may be large enough to look leaf-like.
stolon: a slender, horizontal, above ground stem that roots at its nodes.
strobilus: a cone or cone-like aggregation of sporophylls (modified, spore-bearing leaves).
stomate (stomata plur.): a minute opening in a leaf through which gaseous exchange takes place.
style: part of the pistil between the stigma and ovary.
subsp. subspecies: a taxonomic subdivision of species, usually based on geographic distribution (see Var. variety; also see Introduction).
subtend: to lie below and close to.
succulent: referring to leaves that are fleshy, thick, and juicy.
superior ovary: ovary above the petals, sepals and stamens.
tendril: a slender, coiled, modified leaf that is an organ of climbing plants.
tepal: a sepal or petal that cannot be distinguished from the other.
terminal: at the end.
tooth: a small, marginal lobe, often pointed.
torus: same as receptacle.
trifoliate: a compound leaf with three leaflets.
tripinnate: three times pinnate with primary, secondary, and tertiary divisions.
tuber: a greatly enlarged portion of an underground stem with buds called eyes, like a potato.
umbel: a flat-topped inflorescence with flower stalks (pedicels or peduncles) arising from one point.
var. variety: specifically, a legal term that recognizes a cultivated plant’s breeding; generally, it is almost synonymous with and used interchangeably with “sub species” (see Introduction).
vascular bundle: strands of tissue that support the plant and conduct water and nutrients; composed of sclerenchyma fibers and xylem and phloem (the vascular or conductive tissues).
vegetative: non-reproductive.
whorled: three or more leaves or branches arranged in a circle around a stem.
wing: one of the two side petals of a flower in the pea family, Fabaceae; a thin, flat projection of a dry fruit, like that of a maple.
