Plant Glossary
| Achene |
A non-fleshy, 1-seeded fruit. |
| Alternate |
Type of leaf arrangement in which only a single leaf is attached at each node. Term may also apply to other plant structures attached one per node. |
| Annual |
A plant with a 1-year life cycle, growing from seed, producing flowers and fruits, and dying in 1 year. |
| Anther |
The pollen-bearing part of the stamen. |
| Appressed |
Lying close and flat against another part. |
| Auricle |
A small projecting lobe or appendage, as found at the base of leaf blades of some species of the grass family (Poaceae). |
| Awn |
A slender bristle-tip. |
| Awnless |
Lacking an awn. |
| Axil |
The point of the angle between the stem and leaf attachment. |
| Banner |
The enlarged upper petal of a flower of the pea family (Fabaceae). |
| Basal |
Related to, or located at the base. |
| Beak |
A prolonged, usually narrowed tip of a thicker structure, as in some fruits and petals. |
| Beaked |
Ending in a beak. |
| Biennial |
A plant that lives for two growing seasons, usually flowering only in the second year. |
| Bilateral (symmetry) |
Divisible into identical halves in only one plane; found in "irregular" flowers such as orchids. |
| Blade |
The expanded, flattened part of a leaf or petal. |
| Bract |
A reduced leaf subtending a flower, usually associated with the inflorescence. |
| Bristle |
A hair-like structure; in members of the sunflower family (Asteraceae), it refers to one type of pappus, while in certain members of the sedge family (Cyperaceae) it refers to reduced perianth parts. |
| Bulb |
A short, vertical underground shoot which has modified leaves or thickened leaf bases developed as food storage organs. |
| Bulbil |
A small bulb. |
| Calcareous |
Referring to limestone or lime-rich soils. |
| Callus |
A firm thickening, like the thickened base of the lemma of many grasses (Poaceae). |
| Calyx |
Outer whorl of flowering parts, collective term for all the sepals of a flower, (plural = calyces). |
| Capsule |
A dry fruit that opens by slits, lids, pores, or teeth to release seeds. |
| Catkin |
An inflorescence composed of an often drooping, or pendulous, cluster of unisexual, petal-less flowers, typical of wind pollinated trees and shrubs, such as willows, cottonwoods, oaks, and birches; also called an ament. |
| Chaffy |
Covered by thin, dry scales. |
| Clasping |
Leaf base partly or wholly surrounding the stem. |
| Cobwebby |
With the appearance of spider webbing, usually referring to very fine hairs. |
| Column |
A group of united filaments. |
| Compound (leaf) |
A leaf divided into leaflets. |
| Congested |
Crowded, as in an inflorescence with many densely clustered flowers. |
| Connate |
Grown together or attached in a circle. |
| Contracted |
Narrowed in a particular place. |
| Corolla |
Collective term for all the petals of a flower, these petals may be separate or fused together. |
| Cotyledon |
A leaf of the embryo of the seed. |
| Deciduous |
Falling off; not permanent or evergreen. |
| Decumbent |
Resting on the ground, but with the tip rising up (in contrast to prostrate, in which a structure lies completely flat on the ground). |
| Dehiscent |
Splitting open along regular lines, as in a fruit or anther. |
| Disk |
The tubular flowers found at the center of the flower head of many members of the sunflower family (Asteraceae). |
| Dolabriform (hair) |
Pick-shaped; attached along the middle. |
| Ecotype |
Genetically distinct individuals of a species that are adapted to a particular environment. |
| Elliptic |
Oval shaped, with the ends rounded and the widest point at the middle. |
| Entire |
Undivided; in leaves; having even-edged leaf margins rather than incised or toothed. |
| Erect |
Upright in relation to the ground. |
| Evergreen |
Bearing green leaves or stems over the winter; not deciduous. |
| Farinose |
Covered with a meal-like powder. |
| Fertile |
Bearing or producing reproductive structures. |
| Fibrous (roots) |
Roots with several to many more or less equal branches; lacking a large central taproot. |
| Filiform |
Very slender, threadlike. |
| Flaccid |
Weak and lax. |
| Frond |
The leaf of a fern. |
| Fruit |
The ripened, seed-containing reproductive structure of a plant. |
| Galea |
Upper lip enclosing the anthers in the paintbrush genus (Castilleja) |
| Gametophyte |
The generation which has n chromosomes and produces gametes as reproductive bodies. |
| Glabrous |
Without hairs. |
| Gland |
A depression or appendage which usually secretes a sticky fluid. |
| Glandular |
Bearing glands. |
| Glaucous |
Covered with a waxy coat, often whitish or bluish in color. |
| Glumes |
The pair of bracts at the base of a grass spikelet. |
| Head |
A dense cluster of flowers, usually nearly spherical in outline. Individual flowers in the head are usually sessile or nearly so. |
| Herbaceous |
Non-woody; dying to the ground each year. |
| Hood |
Erect or spreading petal-like blade with incurved margins in the milkweed family (Asclepiadaceae). |
| Horn |
An appendage extending from the hood in the milkweed family (Asclepiadaceae). |
| Indusium |
A covering over the cluster of sporangia in many ferns. |
| Inflated |
A structure that is bladdery or expanded like a balloon. |
| Inflorescence |
The flowering part of a plant, usually referring to a cluster of flowers on a single stem. |
| Inrolled |
Curled or curved inwards; involute. |
| Internode |
The portion of a stem between two successive nodes, the gap between successive points of attachment of leaves on a stem. |
| Interrupted |
Discontinuous; in an inflorescence, having clusters of flowers interspersed with bare areas of stem. |
| Involucre |
A whorl of bracts located beneath (subtending) a flower cluster, as in the heads of members of the sunflower family (Asteraceae). |
| Keel |
A prominent ridge shaped like the keel of a boat; in some members of the pea family (Fabaceae) referring to the lower, boat-shaped petal of the flower that encloses the ovary and stamens. |
| Lacerate |
With an irregularly-jagged margin. |
| Lanceolate |
Lance-shaped, much longer than broad and tapering to a tip. |
| Lateral |
On or at the side. |
| Leaflet |
Any subdivision of a compound leaf. |
| Lemma |
The larger of the two bracts (the other being the palea) that enclose the stamens and pistil in a grass floret. |
| Ligule |
Membranous structure or fringe of hairs found at the junction of the leaf blade and sheath of grasses. |
| Linear |
Several times longer than wide, usually refers to very narrowly shaped leaves or fruits. |
| Lip |
The lowermost, often highly modified, petal of some flowers as in orchids, mints, and penstemons. |
| Lobe |
A division or segment of a structure, usually rounded in outline. |
| Margin |
An edge, as in the edge of a leaf blade. |
| Mealy |
Soft, dry, and crumbly textured, as in certain fruits. |
| Membranous |
Thin, soft, and pliable. |
| Midrib |
The main, central vein of a leaf, bract, scale, or petal. |
| Mucilaginous |
Slimy. |
| Node |
The point of attachment of a leaf or leaves on a stem; the joint of a stem. |
| Nutlet |
A small, one-seeded, nut-like structure; the specialized fruit of members of the borage (Boraginaceae) and mint families (Lamiaceae). |
| Oblanceolate |
A structure that is broadest near the tip and tapering to a narrower base. |
| Oblong |
Much longer than broad, with nearly parallel sides; wider than linear. |
| Once-pinnate |
A compound leaflet divided into entire leaflets (the leaflets are not further divided into lobes or secondary leaflets). |
| Opposite |
Type of leaf arrangement in which two leaves are attached on opposite sides of a stem at the same node. |
| Ovary |
The part of the pistil of a flower that contains the ovules. |
| Ovate |
Egg-shaped, with the broadest end toward the base. |
| Palea |
The smaller of the two bracts (the other being the lemma) that enclose the stamens and pistil in a grass floret. |
| Palmate |
Lobed or veined with 3 or more branches or veins arising from a common point, like the fingers of a hand. |
| Panicle |
A much-branched inflorescence in which the central axis (main stem) bears flowering branches which are themselves branched again. |
| Pappus |
The modified sepals (calyx) of members of the sunflower family (Asteraceae) found at the top of the fruit in the form of thin bristles, feather-like plumes, scales, or sharp awns. |
| Partition |
Line separating the two halves of the fruit of a mustard (Brassicaceae). |
| Pectinate |
Resembling a comb in having very narrow parallel segments borne at a right angle to the main axis. |
| Pedicel |
The stalk of a single flower in a flower cluster, a single fruit, or a single grass spikelet. |
| Peduncle |
The stalk of a flower or flower cluster. |
| Perennial |
A plant which lives for three or more years. |
| Perianth |
Collective term for the calyx and corolla of a flower. |
| Pericarp |
The wall of the fruit. |
| Perigynium |
Sac-like structure enclosing the fruit in species of the cyperus family (Cyperaceae). Plural = perigynia. |
| Persistent |
Remaining attached, as in the calyx on a fruit or remnant, dead leaves. |
| Petal |
The usually colored, individual components of the corolla of a flower. |
| Petiole |
A leaf stalk. |
| Pinnae |
One of the primary divisions of a compound leaf. |
| Pinnate |
With leaflets, lobes, or veins originating from several different points on each side of a main axis, as in the structure of a feather. |
| Pinnately compound |
Division of a leaf blade into leaflets arranged on each side of a common leafstalk. |
| Pistil |
The ovule-bearing structure of a flower, consisting of a stigma, style, and ovary; the "female" part of a flower. |
| Pistillate |
With pistils, but lacking stamens; "female". |
| Plumose |
Feathery. |
| Pod |
Any dry, dehiscent fruit, such as that of many members of the pea family (Fabaceae). |
| Prostrate |
Lying flat upon the ground (in contrast to decumbent in which a structure lies flat on the ground except for the tip which rises upward). |
| Pubescence |
Any type of hair-like structure on a plant part. |
| Pubescent |
Having hairs. |
| Raceme |
An elongate inflorescence made up of stalked flowers attached directly to the main axis. |
| Rachis |
A main axis, such as that of a compound leaf. |
| Ray |
The strap-like flowers at the margin of a head in members of the sunflower family (Asteraceae); a primary branch of the inflorescence in members of the parsley family (Apiaceae). |
| Recurved |
Curved downward or backwards. |
| Reflexed |
Abruptly bent downward or back. |
| Reticulate |
Forming a network pattern. |
| Rhizomatous |
Bearing rhizomes. |
| Rhizome |
An underground stem or rootstock bearing reduced, scaly leaves. |
| Rib |
Prominently raised vein or wing-like structure. |
| Rootstock |
Slow-growing, woody upright underground base of a perennial herb that gives rise to yearly growth of stems and leaves; caudex. |
| Rosette |
A crowded cluster of leaves located at, or near the ground, at the base of a stem. |
| Runner |
A slender stolon. |
| Scabrous |
Rough to the touch like sandpaper, usually due to very short, stiff hairs or outgrowths of the epidermis. |
| Scale |
Any thin, short, often membranous structure; in the sedge family (Cyperaceae) often used in reference to the bracts that subtend individual staminate and Distillate flowers; small, sharp-tipped leaves of certain clubmosses (Lycopodiaceae). |
| Secund |
Oriented on one side of an axis, as in fruits or flowers all being on one side of a stem. |
| Sepal |
An individual leaf-like segment of the calyx of a flower. |
| Sessile |
Lacking a stalk, attached directly at the base (as in a leaf without a petiole). |
| Sheath |
The lower part of the leaf that enfolds the stem in grasses, sedges, and rushes; in horsetails (Equisetum) used to describe the ring of papery leaves at each stem joint. |
| Shrub |
A woody plant with several equally large stems from the base, usually less than 4.5 m tall. |
| Silique |
A fruit type found in certain members of the mustard family (Brassicaceae) characterized by its long, slender shape that is typically 3 or more times longer than wide. |
| Simple |
Unbranched or undivided; in leaves refers to condition in which leaves are not divided into leaflets. |
| Sorus |
A cluster of sporangia (plural=sori). |
| Spike |
An elongated inflorescence of sessile flowers or florets. |
| Spikelet |
The basic unit of the inflorescence of grasses and sedges. In grasses (Poaceae), it is composed of a pair of basal glumes subtending 1 or more florets. In sedges (Cyperaceae) it consists of a single bract subtending a flower. |
| Sporangium |
A case or container for spores (plural=sporangia). |
| Spore |
The reproductive body produced and dispersed by ferns, horsetails, club mosses and other "lower" vascular plants that do not reproduce by true seeds. |
| Sporophyll |
A leaf which bears or subtends 1-more sporangia. |
| Spreading |
Diverging at nearly a right angle from a structure; nearly prostrate. |
| Spur |
A tubular or sac-shaped extension of a petal or sepal. |
| Stamen |
The pollen-producing structures of a flower; the "male" part of a flower. |
| Staminate |
With stamens, but lacking a pistil; "male". |
| Staminode |
A modified stamen which does not produce pollen. |
| Sterile |
Non-fertile; structure lacking reproductive parts or abilities. |
| Stigma |
The surface of the pistil on which pollen grains land and germinate. |
| Stipule |
Leaf-like or scaly appendages (typically paired) at the base of the petiole in many plants. These may be fused at the base as in some members of the pea family (Fabaceae). |
| Stolon |
A horizontal stem, usually growing along the surface of the ground, often giving rise to new plants at its tip; runner. |
| Strobilus |
Cone-like reproductive structure; spore-bearing structure of horsetails (Equisetaceae) and clubmosses (Lycopodiaceae; plural = strobili.) |
| Style |
The portion of the pistil between the ovary and the stigma. |
| Subtend |
To be situated immediately below, as in bracts beneath a flower. |
| Taproot |
The primary root from which secondary (smaller, lateral) roots arise. |
| Tendril |
A slender, coiling or twining organ by which a plant clings to a support. |
| Tepal |
A segment of the perianth not clearly differentiated between sepals and petals. |
| Terminal |
Located at the tip of a structure. |
| Ternately compound |
Divided into threes, as in a leaf consisting of three leaflets. |
| Tooth |
Any small, marginal lobe, usually on the edge of a leaf blade. |
| Tufted |
A close-growing cluster of stems, as in certain bunchgrasses, sedges, and mat-forming herbs. |
| Tussock |
A compact, densely tufted growth form of some grasses and sedges. |
| Twig |
The current year's growth of a woody stem; the endmost section of a branch. |
| Umbel |
A flower cluster in which the individual flower stalks arise from a common point, like the rays of an umbrella. |
| Valve |
One of the segments into which a dehiscent fruit separates. |
| Vegetative |
A sterile structure of a plant, not associated with the production or dissemination of seeds, spores, or pollen. |
| Vein |
A vascular bundle of a leaf or petal; nerve. |
| Viscid |
Sticky; with sticky exudates. |
| Whorl |
a ring of 3-more similar structures radiating from a common point. |
| Wing |
A thin, often dry or leaf-like extension bordering a structure; also referring to the 2 lateral petals of the flower in some members of the pea family (Fabaceae). |
| Woolly |
with long, interwoven hairs. |
