OSU Students





Glossary of Taxonomic Terms

Accessory bud: located beside or above the true bud at a node.

Achene: a small,dry, indehiscent fruit.

Acorn: the fruit of oaks; a thick-walled nut with a woody cup-like cap.

Acute: having an apex or base with sides tapering to a point.

Aggregate flower: heaped or crowded into a dense cluster.

Aggregate fruit: a fruit that has developed from a flower having many pistils on a common receptacle.

Alternate: a leaf arrangement with leaves placed singly at various heights and on different sides of a stem.

Anther: pollen-bearing part of the stamen.

Apex: the terminal end or tip.

Apical: describes the apex or tip.

Appressed: lies flat and pressed close to the stem.

Apetalous: lacking petals.

Auriculate: having two rounded, ear-shaped lobes as projections of some leaf and petal bases.

Berry: a fleshy, indehiscent, multi-seeded, pulpy fruit.

Bipinnate: twice pinnate.

Bract: a modified protective leaf associated with the inflorescence, buds, or with newly emerging buds and stems.

Branchlet: a small branch or twig; a division of a larger branch.

Bristle: a stiff hair.

Broad-elliptic: wider than elliptic.

Broad-ovate: wider than ovate.

Bud: a structure of embryonic tissues which will become a flower, leaf, both, or a new shoot.

Bud scale: a modified leaf or stipule protective of the embryonic tissue of the bud.

Campanulate: bell-shaped.

Capsule: a dry, dehiscent fruit.

Catkin: a cylindrical, spike-like inflorescence comprised of pistillate or staminate (unisexual) flowers, usually apetalous.

Channeled: grooved lengthwise.

Collateral buds: accessory buds to either side of the true lateral bud at a node.

Compound leaf: a leaf composed of two or more leaflets on a common petiole.

Cone: a coniferous fruit having a number of woody, leathery, or fleshy scales, each bearing one or more seeds and attached to a central axis.

Conical: cone-shaped; tapering evenly from base to apex in three dimensions.

Cordate: heart-shaped.

Corregated: crumpled or wrinkled, but more loosely than in rugose.

Corymb: an indeterminate, flat-topped inflorescence whose outer flowers open first.

Crenate: rounded teeth on leaf margins.

Crenate-serrate: having a mixture of blunt and sharp teeth.

Cuneate: wedge-shaped.

Cylindrical: elongated and virtually circular in cross-section.

Cyme: a flat-topped, determinate inflorescence whose outer flowers open last.

Dehiscent: splitting open of a seed capsule along the sides or segments to release seeds when ripe; also the opening of anthers to release pollen.

Dentate: toothed leaf margins whose apices are perpendicular to the margin and do not point forward.

Determinate: refers to inflorescences such as cymes where the terminal flower opens first and the lower flowers open last.

Dioecious: having male and female flowers on different plants.

Divergent: spreading broadly.

Downy: pubescent with soft, fine hairs.

Drupe: indehiscent fruit whose seed is enclosed in a stony endocarp contained within soft, fleshy pericarp. Ex. Cherry, Plum

Ellipsoid: three dimensional shape of an ellipse; foot-ball shaped.

Elliptic: ellipse-shaped, with equally rounded or narrowed ends with two planes of symmetry and widest across the middle.

Endocarp: the innermost layer or wall of the pericarp, enclosing the seed.

Entire: a leaf whose margin does not have teeth or indentations.

Exfoliating: peeling off in layers.

Fissure: a narrow, horizontal or vertical crack with straight sides.

Fluted: having long, rounded, vertical ridges.

Furrowed: having longitudinal channels or grooves.

Glabrous: hairless.

Glaucous: covered with a waxy bloom or whitish material that rubs off easily.

Imbricate: overlapping.

Imperfect flower: lacking either pistils or stamens.

Indeterminate: refers to inflorescences whose terminal flowers open last and lower flowers open first.

Invasive: weedy; usually grows under most soil conditions and where the soil is poor.

Lanceolate: much longer than wide; broadest below the middle and tapering to the apex.

Lateral: on or to the side.

Lenticel: a small, corky pore on young bark through which gasses are exchanged.

Linear: very narrow and long.

Lobe: a division of a leaf or petal that cuts into the margin.

Margin: the edge of a leaf blade or flower petal.

Monoecious: staminate and pistillate flowers are present on the same plant.

Naked bud: without scales.

Necrosis: death associated with discoloration and dehydration of all or some parts of plant organs.

Needle: a linear stiff leaf of many conifers.

Node: a joint on a stem, represented by point of origin of a leaf or bud.

Nut: a dry, indehiscent, single-seeded fruit with a hard woody pericarp (shell), such as a walnut and pecan.

Oblique: Uneven or lop-sided, as the base of an elm leaf.

Oblong: longer than broad with nearly parallel sides.

Obovate: ovate, but broadest above the middle, thus narrowest toward the base rather than the apex.

Obovoid: three-dimensional shape of obovate, pear-shaped.

Opposite: an arrangement of leaves or buds in paired at a node.

Ovate: egg-shaped, rounded at both ends but broadest below the middle.

Ovoid: three-dimensionally egg-shaped.

Palmate: having three or more veins arising from the point of attachment of the petiole.

Panicle: an indeterminate branched inflorescence.

Parallel: running side by side from base to tip, as in veins of a leaf.

Pedicel: the stalk of a flower or fruit when clustered or solitary.

Peduncle: the stalk of a flower cluster or a single flower when that flower is solitary.

Pendulous: hanging or declined.

Perfect flower: having both stamens and pistils.

Pericarp: the wall of a ripened ovary or fruit

Persistant: adhering to position instead of falling off whether dead or alive.

Pinnate: feather-like; having two rows of leaflets along a rachis.

Pistil: female organ comprised of the stigma, style, and ovary.

Pistillate: having pistils, but no stamens.

Pith: the central part of a twig, usually lighter or darker than the wood.

Pitted: marked with small depressions.

Pod: a dry, dehiscent fruit.

Pome: a fleshy fruit comprised of a central core with seeds resulting from a compound ovary as in an apple or pear.

Pubescent: covered with short, fine, soft hairs.

Pyramidal: pyramid-shaped; broadest at base.

Raceme: an inderterminate, unbranched inflorescence in which the flowers are borne in short pedicels along a central axis.

Racemose: having flowers in racemes.

Rachis: the central axis of a compound leaf.

Ranked: foliage is arranged in longitudinal planes around the stem.

Reflexed: bent abruptly backward or downward.

Resinous: containing or exuding resin.

Reticulate: netted; network of veins.

Rhombic: diamond-shaped; having four nearly equal sides, but unequal angles.

Rhombic-ovate: between egg and diamond-shaped.

Rugose: wrinkled.

Samara: a dry, indehiscent fruit bearing a wing as in maple or ash.

Scabrous: rough or gritty to the touch; rough pubescent.

Scale: a small, dry bract usually covering a bud.

Scurfy: a surface covered with bran-like particles.

Serrate: saw-toothed; teeth pointing forward.

Serrulate: minutely serrate.

Sessile: without a stalk.

Simple leaf: a leaf not divided into leaflets; not compound.

Sinus: the space between two lobes, segments, or divisions.

Solitary: occurring or borne singly.

Spatulate: spoon-shaped.

Spike: an indeterminate inflorescence bearing sessile flowers on an unbranched axis.

Stamen: pollen-bearing organ, consisting of the anther and filament.

Stellate-pubescent: with hairs in small star-like tufts.

Stipule: an appendage, often leaf-like, of the petiole.

Subtend: to be placed directly below a different organ or structure often sheathing or enclosing it.

Superposed bud: accessory bud above the true lateral bud.

Terminal: at the tip.

Tomentose: densely woolly, with short, soft hairs.

Torulose: twisted or knobby.

Trifoliate: compound leaf with three leaflets.

Umbel: an indeterminate, usually flat-topped inflorescence in which the pedicels of the flowers arise from a common point, resembling the frame-work of an umbrella.

Undulate: wavy, in an up and down direction, not in and out.

Valvate: describing parts with touching but not overlapping margins.

Whorl: an arrangement of three or more leaves or buds at a node.

Woolly: having soft, long, matted hairs; like wool.


Dirr, M.A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Stipes Publishing Company, Champaign, IL.

Griffiths, M. 1994. Index of Garden Plants. Timber Press, Portland, OR.

Hartman, H.T., Kofranek, A.M., Rubatzky, V.E., Flocker, W. J. 1988. Plant Science: Growth, Development, and Utilization of Cultivated Plants. Prentice Hall, Englewood Cliffs, New Jersey.

Yiesla, S.A. 1992. Shade Trees for the Central and Northern United States and Canada. Stipes Publishing Company, Champaign, IL.