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Glossary of Botanical Terms

Following is a glossary of botanical terms used mostly in pages posted under the heading Botany For Gardeners or Plant Profiles. Botanical terms used on these pages are highlighted and when clicked-on, take the reader directly to this glossary. Use the “back-button” to return to the page you were reading.

Achene. A small dry, hard 1-locular, 1-seeded indehiscent fruit with a thin pericarp, derived from a 1-carpellate ovary.
Aculeate. Prickly; beset with prickles.
Acuminate. Tapering at the end; long pointed.
Acuminulate. Abruptly ending in a short point.
Acute. Sharp-pointed; ending in a point.
Allelopathic. A plant which produces chemicals that influence the growth, survival, and reproduction of nearby plants.
Alternate. Not opposite to each other on the axis.
Andro-dioecious. Staminate and bisexual flowers on different plants.
Androgynous. With both staminate and pistillate flowers in the same inflorescence.
Andro-monoecious. Staminate and bisexual flowers on the same plant.
Angiosperm. Plants having seeds in a closed ovary.
Annular. In the form of a ring.
Anther. The pollen-bearing part of the stamen.
Anthocyanins. Pigments producing reddish or purplish coloring in plants.
Apetalous. Flowers having no petals.
Apical meristem. The cluster of meristematic cells at the tip of a shoot or root.
Arachnoid. Having fine, entangled hairs like a cobweb.
Attenuate. Slenderly tapering.
Axil. The upper angle formed by a leaf or branch with the stem.
Axillary. Situated in an axil.
Axis. The central line of an organ or the support of a group of organs.
Basal. located at the base of a plant; arising directly from the root.
Berry. A fruit with the whole pericarp fleshy or pulpy
Biennial. A plant having a life cycle that takes two seasons from germination to
death; flowering biennials usually bloom and fruit in the second season.
Bilateral Symmetry. Having identical parts on each side of an axis.
Blade. The expanded portion of the leaf.
Bract. A modified reduced leaf subtending a pedicel or peduncle or belonging to an inflorescence or occurring at the base of shoots.
Branch Axil: The angle formed where a branch joins another branch or stem of a woody plant.
Branch Collar: A “shoulder” or bulge formed at the base (bottom) of a tree branch by the annual production of overlapping layers of branch and stem tissues.
Branch Bark Ridge: A ridge of bark that forms at the top of a tree branch crotch and partially around the stem resulting from the growth of the stem and branch tissues against one another.
Calyx (calyces). The whorl or sepals of a flower collectively forming the outer floral envelope or layer of the perianth enclosing and supporting the developing bud; usually green in color.
Carotenoios. Pigments producing yellow and orange coloring in plants.
Chlorophyll. The green colored pigment visible in leaves and present in all growing plants.
Cambium. Soft layer-like sheath which surrounds phloem and xylem in dicotyledon and gymnosperm plants.
Carpel. A simple pistil or a member of a compound pistil.
Catkin. A scaly-bracted spike of usually unisexual flowers.
Ciliate. Fringed with hairs.
Columnar. Having the shape of a column.
Compound. Composed of two or more similar parts as a compound leaf, or an inflorscence with the flowers on axes of the second or a higher order.
Cordate. Heart-shape; usually referring to the base of a leaf with two rounded lobes and a sinus.
Coriaceous. Of leathery texture.
Corolla. The inner, usually colored or otherwise differentiated, whorl or whorls of the perianth.
Corymb. A form of inflorescence in which the flowers form a flat-topped or convex cluster, the outermost flowers being the first to open.
Cortex. The part of a primary root or stem located between the epidermis and the vascular cylinder.
Catkin. A scaly-bracted, usually flexuous spike or spike-like inflorescence.
Cotyledon. An embryonic leaf or leaves in seed-bearing plants.
Crenate. Toothed with rounded, shallow teeth.
Cuspidate. Sharp-pointed; ending in a sharp pointed cusp.
Cyme. A broad, flattish determinate inflorescence, the central flowers maturing first.
Deciduous. Falling, not persistent.
Deliquescent. Trunk of a tree dividing into several stems or limbs.
Dentate. Toothed with the teeth directed outward.
Denticulate. Minutely dentate.
Dicots. A plant having two cotyledons, or seed leaves. One of two sub-classes of angiosperms that include most deciduous trees and shrubs.
Dioecious. Staminate and pistillate flowers on different plants
Downy. Having very short, weak, and soft hairs.
Drupe. A fleshy indehiscent fruit with a bony, usually one-seeded endocarp.
Elliptic. With an outline of an ellipse.
Embryo. The rudimentary plant within the seed.
Endodermis. The innermost layer of small, close-fitting cells of the cortex of a root that form a ring around the vascular cylinder.
Epidermis. The outermost layer of cells of a leaf, young root, or young stem.
Epiphytic. Growing on other plants, but not parasitic.
Etiolate. Elongated stems, developed without chlorophyll by being deprived of light.
Exfoliating. Peeling off in thin layers.
Farinose. Mealy, with a covering of waxy, whitish powder.
Fastigiate. With stems or branches erect and near together.
Floccose. Clothed with flocks of soft hair or wooly hairs that tend to rub off.
Fertile. Capable of producing fruit or seeds.
Fruit. Seed-bearing product of a plant.
Furrowed. With longitudinal channels or grooves.
Geotropic response. The growth of a plant in response to gravity, as the downward
growth of roots.
Glaborous. Not hairy.
Glaucous. Covered with a bloom; bluish white or bluish gray.
Globose. Globular or spherical.
Glucose. A sugar, C6H12O6, that is the end product of photosynthesis.
Glutinous. Sticky.
Gymnosperms. The group of plants having naked seeds or without an ovary.
Hemiparasite. A parasitic plant that contains some chlorophyll and therefore is capable of photosynthesis.
Herbaceous. Characteristic of a non-woody plant.
Hirsute. With rather course or stiff hairs.
Hispid. Beset with rigid hairs or bristles.
Hybrid. A plant resulting from a cross between tow or more parents that are more or less unlike.
Imbricate. Overlapping, as shingles on a roof.
Incised. Sharply and more or less deeply and irregularly cut.
Inflorescence. The flowering part of the plant.
Internode. A segment of a stem between two nodes.
Involucre. A whorl of bracts surrounding a flower-cluster or a single flower.
Lanceolate. Shaped like a lance head; narrow and tapering to a pointed apex.
Leaflets. Part of a compound leaf.
Lenticular. Lens-shaped, biconvex, e.g., marks on bark.
Ligule. Spreading limb of ray flowers; a projection at the base of the leaf blade in some ferns.
Mesic. Characterized by moderate or a well-balanced supply of moisture.
Midrib/Midvein. The central vein or rib of a leaf.
Monadelphous. Stamens united in one group by their filaments.
Monoecious. With unisexual flowers of both sexes on the same plant.
Monocots. A plant having one cotyledon, or seed leaves. One of two sub-classes of angiosperms that include most grasses, lilies, orchids and palms.
Mucilaginous. Having the sticky properties of an adhesive.
Node. The small swelling on a stem which one or more leaves emerge.
Nut. An indehiscent one-seeded hard and bony fruit.
Nutlet. A small nut, or hard mericarp as in the Cyperaceae or Polygonaceae.
Obcordate. Inversely heart-shaped.
Oblique. Unequal-sided.
Oblong. About three times as long as wide and with nearly parallel sides.
Ovary. The ovule-bearing part of the pistil.
Ovate. Shaped like an egg; oval.
Ovule. The body which after fertilization becomes the seed.
Palmate (leaf). Radiately lobed or divided, with three or more veins arising from one point.
Panicles. A compound raceme
Pedicel. The stalk of a flower.
Pendulous. Hanging.
Perianth. The outer envelope of a flower, consisting of either the calyx or the corolla, or both.
Pericycle. The outermost layer of cells of the vascular cylinder of a root.
Petiole. Leaf-stalk.
Perfect (flower). Having both stamens and pistil; bisexual.
Persistent. Remaining attached; not falling off.
Petal. One of the separate leaves of the corolla.
Petiole. Leaf-stalk.
Petiolule. Stalk of a leaflet.
Phloem. A conducting tissue of vascular plants that transports a concentrated sugar solution up and down the plant.
Photosynthesis. Formation of carbohydrates in the chlorophyll-containing tissues of plants exposed to light.
Pinnae. The divisions of a compound frond, analogous to the leaflets of a compound leaf.
Pinnate (pinnate-veined leaf). Feather-veined; the main veins more or less at right angles to a main midrib.
Pistil. the seed-bearing organ of the blower consisting of ovary, style and stigma.
Pith. Center of the stem in herbaceous annual and perennial dicots.
Pod. A dry dehiscent fruit.
Pollen. Spores or grains borne by the anther, usually granular.
Polygamous. Bearing unisexual and bisexual flowers on the same plant.
Pome. A fleshy fruit like the apple and the pear.
Prostrate. Lying on the ground or trailing.
Pubescent. Covered with hairs, particularly if short and soft.
Raceme. A simple inflorescence of stalked flowers on a more or less elongated rachis.
Rachis. An axis bearing flowers or leaflets.
Radiate. Spreading from a common center.
Radicle. A small structure resembling a root on a seed.
Rosette. An arrangement of leaves radiating from a crown or center, usually at or close to the earth.
Recurved. A flower petal or leaf that is curved backward or inward.
Reflexed. Abruptly recurved or bent downward or backward.
Resin-ducts. Canals in the plant-tissue containing resin.
Rhizoid. A root-like structure found in bryophytes that anchors the plant and absorbes water and nutrients from the soil.
Rhizome. An underground stem, usually horizontal, that stores food.
Rib. A primary or prominent vein in a leaf.
Root cap. A cluster of cells at the tip of a growing root, derived from the apical meristem; protects the growing tip as it burrows through the soil.
Rugose. Wrinkled.
Sagittate. Shaped like an arrow-head, with the basal lobes directed downward.
Samara. Indehiscent winged fruit, as of Ulmus and Fraxinus.
Scabrose. Rough to the touch.
Scale. A minute leaf or bract; minute gland-like flat appendages of the epidermis.
Scape. Erect leafless flower stalk growing directly from the ground as in a tulip.
Sessil. Not stalked.
Seed. The ripened ovule consisting of the embryo and its integuments.
Sepal. A division, or one part of the calyx.
Serrate. With sharp teeth pointed forward.
Sessile. Without petiole, or pedicel.
Shrub. A woody plant branched from the base.
Silky. Covered with appressed fine and straight hairs.
Sorus. The cluster of sporangia of ferns
Spadix. A spike with fleshy axis, often surrounded by a spathe.
Spathe. A conspicuous bract surrounding a spadix or other inflorescence.
Spike. A simple inflorescence with the flowers sessile or nearly so on a common axis.
Sporangium. A spore case.
Spur. A tubular or sac-like projection from a petal or sepal.
Stamen. The pollen-bearing male organ of the flower.
Stem. The main axis of a plant.
Stigma. The part of the pistil that receives the pollen.
Stipe. The stalk of a pistil; also, the petiole of a fern leaf.
Stipules. An appendage of the base of the petiole, usually one on each side.
Stolon A horizontal stem from the base of a plant that produces new plants from buds at its tips.
Stoloniferous Producing stolons.
Stomata. Small openings in the epidermis of plant leaves.
Style. The more or less elongated part of the pistil between the ovary and the stigma.
Tendril. A coiling thread-like organ by which a plant grasps an object for support
Tomentose. With dense woolly pubescence.
Transpiration. The process of passing CO2 and water vapor through leaf stomata.
Trifoliolate. Having three leaflets.
Tuber. A fleshy underground stem that is a food storage organ of a plant.
Tunic. An enveloping or covering membrane, e.g., onion skin.
Umbel. Flat-topped inflorescence (characteristic of Umbelliferae family) which individual flower stalks arise from the same point; youngest flowers at the center.
Vascular Bundle. A fascicle or phloem and xylem found in monocots.
Vascular Tissue. Plant tissue containing the xylem and phloem.
Veins. Threads of fibro-vascular tissue in a leaf or similar organ; nerves, but especially the smaller branched nerves.
Venation. Arrangement of veins.
Whorl. An arrangement of three or more organs in a circle around the axis.
Xylem. A conductiing tissue of vascular plants that transports water and minerals from the root to shoot.