Acuminate – With a long-tapered, sharp tip, the sides concave.
Androdioecious – Having staminate and perfect flowers on separate plants.
Anther – Portion of the stamen that produces pollen.
Appendage – A secondary part attached to a main structure.
Appressed – Growing against or very close to another part of the plant.
Ascending – Curving upward from base; about 30-60° < vertical or away from axis of attachment.
Auricule – An ear-shaped appendage. Auriculate= bearing auricles.
Awl-like – Broad-based and tapered to a sharp tip.
Awn – 1. Bristle-like appendage or elongation, gen at tip. 2. Stiff, needle-like pappus element in the Asteraceae.
Axil – Upper angle formed by a leaf or branch with the stem. axillary = in an axil.
Axis – Line of direction, growth, or extension; structure occupying such a position (e.g. main stem of plant or inflorescence, midrib of leaf).
Banner – Uppermost, often largest petal of many members of the Fabaceae.
Basal – At or near base of plant or plant part; especially pertaining to leaves clustered near ground.
Beak – A narrow or prolonged tip, as on some fruits and seeds.
Bell-shaped – Pertaining to a fused calyx or corolla that widens ± abruptly at base and gen more gradually above.
Bilateral – Divisible into mirror-image halves in only 1 way. cf. radial.
Blade – Flat, expanded portion of a leaf, petal, or other structure.
Bract – A modified leaf at or near the base of a flower or inflorescence.
Bractlet – A relatively small, gen secondary bract within an inflorescence, or a bract-like structure on a pedicel.
Bristle – 1. Relatively large, gen stiff, ± straight hair. 2. Fine, gen cylindric pappus element in the fruit of the Asteraceae.
Bud – Unopened flower, often protected by sepals.
Bur – Fruit or fruit inflorescence with awns or bristles, often barbed, that attaches to and is dispersed by an animal.
Burl – A rounded knotty growth on a tree or shrub.
Callosity – A hard, thickened lump on the inner perianth lobes of some species of Rumex.
Calyx (pl. calyces) – All of the sepals taken together; outermost or lowermost whorl of flower parts; gen green and enclosing remainder of flower in bud; sometimes indistinguishable from corolla.
Capsule – Dry, gen many-seeded fruit from compound pistil, nearly always dehiscent, irregularly or by pores, slits, or lines of separation.
Cauline – Borne on a stem, not basal (generally of leaves).
Ciliate – Having generally straight, prominent hairs on margins.
Circumboreal – Relating to, distributed, or occurring chiefly throughout the northern portion of the Northern Hemisphere.
Circumscissile – Dehiscent by a transverse line, the top coming off as a lid.
Clasping – A leaf that partly surrounds the stem. cf. perfoliate.
Claw– A stalk-like base of some sepals or petals; also the base of the keel in lupines and other Fabaceae.
Compound – 1. Composed of 2 or more parts. 2. Repeating a structural pattern, as a compound umbel is an umbel of umbels.
Compound leaf – A leaf divided into distinct parts, connected by an axis but no blade material. If these leaflets are again divided into distinct parts, the leaf is twice-compound, etc. cf. dissected.
Cordate – Heart-shaped with notch at base.
Corolla – All of the petals taken together.
Crenate – Scalloped; margins with shallow, rounded teeth.
Crisped – Curled, wavy or crinkled.
Cylindric – Elongate with parallel sides and at any point circular in cross section.
Cyme – A branching inflorescence with flowers maturing from the top downwards. cymose, adj.
Deciduous – Falling off naturally at the end of a growing period; gen pertains to leaves that fall seasonally and all together, or to plants that are seasonally leafless.
Decumbent – Lying on the ground with the tip pointing upwards.
Decurrent – (Leaves) The base extending down the stem from the apparent point of insertion.
Deltoid, Deltate – With the shape of the Greek letter delta; shaped like an equilateral triangle.
Dentate – Pertaining to margins with sharp, relatively coarse teeth pointing outward instead of towards the tip as in serrate.
Dioecious – Male & female flowers on separate plants; pertains to a taxon in which individuals produce either male or female fertile reproductive structures, but not both.
Disciform head – In the Asteraceae, a head comprised of disk flowers and marginal pistillate (or sterile) flowers with rays minute or 0, so resembling a discoid head.
Discoid head – In the Asteraceae, a head comprised exclusively of disk flowers.
Disk flower – In the Asteraceae, the tubular 5 (rarely 4-) lobed corollas of the head appearing with or without ray flowers.
Distal – Towards the tip, further from the base or point of attachment. cf. proximal.
Drupe – Fleshy or pulpy indehiscent fruit from pistil of 1 or more ovaries in which a single seed is encased in a stone, or seeds are encased individually in free or fused stones.
Elliptic – In the shape of a flattened circle or ellipse. ellipsoid = an elliptical solid.
Exserted – Projecting beyond the surrounding structure (often used in relation to stamens).
Fascicle – A close cluster or bundle of flowers, leaves, stems or roots. fasciculate, adj.
Filament – Portion of the stamen that supports the anther.
Filiform – Threadlike.
Fleshy – Thick and juicy; succulent.
Frond – Leaf of a fern.
Fruit – A ripened ovary; an ovary or ovaries and sometimes associated structures after ovule fertilization.
Glabrous – Smooth, without hairs.
Gland – A small, gen spheric body that secretes a gen sticky substance, located on epidermis or at the tip of a hair.
Glaucous – Covered with a gen whitish or bluish waxy or powdery film that is sometimes easily rubbed off.
Graduated – With parts of progressively different lengths.
Hastate – Arrowhead-shaped, but with 2 basal lobes oriented ± perpendicular to the long axis.
Head – Dense, often spheric inflorescence of sessile or subsessile flowers.
Herb – A plant that has little or no wood above ground; above ground parts are of < 1 year’s duration. herbaceous, adj.
Hip – A berry-like structure composed of an enlarged hypanthium surrounding numerous fruits, as in roses.
Horn – A tapering projection resembling the horn of a cow.
Hybrid – A cross between two species.
Hypanthium – A cup-shaped enlargement of the receptacle on which the calyx, corolla, & often the stamens are inserted.
Indusium – In many ferns, a veil- or scale-like outgrowth of the leaf surface or margin that covers a cluster of sporangia.
Inflorescence – An entire cluster of flowers & associated structures (e.g. bracts, pedicels, etc); often difficult to define as to type and boundaries.
Intergrade – To merge gradually from one extreme to another through a ± continuous series of intermediates.
Interrupted – With parts spaced unevenly; generally pertaining to inflorescences in which the axis is visible between flower clusters.
Involucre – Group of bracts subtending a flower, fruit or inflorescence, more or less held together as a unit.
Keel – 1. Ridge or crease ± centrally located along the long axis of a structure, gen on the under or outer side. 2. The 2 lowermost, fused petals of many members of the Fabaceae.
Lanceolate – Lance–shaped, attached at the broad end. cf. oblanceolate.
Leaflets – A leaf-like unit of a compound leaf.
Lemma – In Poaceae, the lower, generally larger, of 2 sheathing bracts subtending a flower.
Ligule – In the Asteraceae, bisexual, 5-lobed, strap-like outer portion of corolla. cf. ray flower. ligulate, adj.
Linear – Very narrowly elongate and with nearly parallel sides, gen of leaves.
Lobe – 1. A major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. The free tips of otherwise fused structures, such as sepals or petals.
Monoecious – Male and female unisexual flowers on the same plant; pertains to a taxon in which individuals produce both male and female but no bisexual reproductive structures.
Mucronate – Having a small, short, abrupt tip, or mucro.
Nascent – Starting to develop but not yet fully formed.
Node – The join of a stem; gen the point of insertion of a leaf or leaves.
Nut – Mostly dry, indehiscent fruit from pistil of 1 or more ovaries in which a single seed, often edible, is encased in a hard shell.
Nutlet – Small nut or nut-like fruit, gen one of several produced by a single flower, gen inedible.
Ob – Prefix signifying inversion of shape (e.g. ovate leaves are widest below & obovate are widest above the middle).
Oblanceolate – Inversely lanceolate with the attachment at the narrower end.
Oblong – Longer than broad, with nearly parallel sides and rounded corners, not as narrow as linear.
Obtuse – With short-tapered, blunt tip or base, the sides convex or straight and converging at more than a right angle.
Ocrea (pl. ocreae) – (Polygonaceae) Generally scarious sheath around the stem caused by the fusion of stipules.
Ovate – Egg-shaped (i.e. widest below middle); applied to 2-dimensional objects, esp. leaves. Inverse = obovate.
Palmate – Radiating from a common point; gen pertaining to veins, lobes of leaflets of a leaf.
Panicle – Branched inflorescence in which the basal or lateral flowers open before the terminal or central flowers. cf. cyme. paniculate, adj.
Papillate, Papillose – Pertaining to surfaces bearing small rounded or conic protuberances.
Pappus – In Asteraceae, structures (e.g. awns, bristles, scales) arising from top of inferior ovary in place of sepals. Pappose = with pappus.
Parasite – A plant that takes food and water from a physical connection to another plant of a different species.
Pedicel – The stalk of an individual flower or fruit in an inflorescence.
Peduncle – Stalk of an entire inflorescence or of a flower or fruit not borne in an inflorescence.
Peltate – Parasol-shaped; a flat body having the stalk attached to the lower surface instead of at the base or margin.
Pendent – Drooping, hanging, or suspended from the point of attachment above.
Perianth – Calyx and corolla collectively, whether or not they are distinguishable.
Perianth part – Generally used to describe part of a flower which does not have distinguishable petals and sepals.
Petal – Lobe of the corolla, whether fused or not; often conspicuously colored. petaloid = resembling petals.
Petiole – The stalk of a leaf.
Phyllary – In Asteraceae, a bract of the involucre that subtends a head.
Pinna – Leaflet or primary division of a pinnate leaf.
Pinnate – (leaves) Having two rows of leaflets on either side of a central axis.
Pinnatifid – (leaves) Pinnately cleft into narrow lobes not reaching to the midrib.
Pinnule – Division of a pinna.
Pistil – Female reproductive structure of a flower composed of ovary at the base, 1 or more pollen-receiving stigmas at the tip, & often 1 or more styles between.
Plumose – Feathery, having fine hairs on each side as a plume.
Pollen – The male reproductive bodies produced in an anther.
Prickle – Sharp outgrowth of the bark or epidermis. prickly = armed with prickles, as the rose.
Prostrate – Lying flat upon the ground.
Proximal – Closer to the base or point of attachment, further away from the tip. cf. distal.
Punctate – Dotted with punctures, or with translucent pitted glands, or with colored dots.
Puberulent – Minutely pubescent.
Pubescent – Covered with short, soft hairs; downy.
Raceme – A flower head with the flowers maturing from the bottom upwards.
Rachis – Axis of a spike or raceme, or of a compound leaf.
Radial – Divisible into mirror-image halves in 3 or more ways. cf. bilateral.
Ray flower – In Asteraceae, one of the sterile or pistillate strap-like marginal flowers, often 3-lobed, appearing with central disk flowers. cf. ligule.
Receptacle – 1. In individual flowers, structure to which flower parts are attached. 2. In heads or head-like inflorescences, especially in the Asteraceae, structure to which flowers are attached.
Reflexed – Curving sharply outwards and/or downwards. produced during the most recent or current growth period.
Rhomboid – Somewhat diamond-shaped.
Rosette – A radiating cluster of leaves gen at or near ground level.
Sagittate – Arrowhead-shaped with 2 basal lobes oriented nearly parallel to the long axis.
Samara – An indehiscent winged fruit, esp on Acer.
Scale – Any thin, flat, dry, membranous structure – not green.
Seed Pod – Any dry, dehiscent fruit; specifically, a legume.
Sepal – Part of the calyx (typically surrounding the flower when in bud).
Serpentine – Pertaining to rocks or soils with generally low levels of calcium and other nutrients and high levels of magnesium, iron and certain toxic metals. Many plants are restricted to or excluded from serpentine.
Serrated – (leaves) Toothed with the individual teeth facing tipward, not outward.
Sessile – Attaching directly to a stem. Subsessile = almost sessile.
Sheath – The portion of an organ which surrounds, at least partly, another organ, e.g. the base of a grass leaf blade which surrounds the stem.
Sinus – The cleft or depression formed between 2 lobes of an expanded organ such as a petal or leaf.
Sorus (pl. sori) – (found on the underside of fern leaves) – An oblong or round cluster of distinct sporangia.
Spatulate – Like a spatula, rounded above and narrowed to the base.
Spike – An unbranched inflorescence with sessile / subsessile flowers nearly always opening from bottom to top.
Spikelet – In Poaceae, the smallest aggregation of florets plus the 2, usually subtending, glumes; in Cyperaceae, the smallest aggregation of flowers (gen > 2) and associated bracts.
Spine – A sharp-pointed stiff woody body, arising from below the epidermis, gen the counterpart of a leaf or stipule. spinose, adj.
Sporangium (pl. sporangia) – In non-seed plants (ferns & fern allies), a spore-producing case or sac.
Spreading – Diverging almost to the horizontal.
Spur – A hollow and slender extension of some part of a flower.
Stamen – The male reproductive organ, comprising filament and anther, and bearing pollen.
Staminate – 1. Having stamens. 2. Pertaining to flowers, inflorescences, or plants with fertile stamens but sterile or missing pistils.
Staminode – A sterile stamen (lacking an anther) or structure corresponding to a stamen, gen modified in appearance, sometimes petal-like.
Stellate – (Hairs) star-shaped, with many hairs radiating out from the base.
Stigma – The part of the pistil on which pollen is normally deposited, gen terminal & elevated above the ovary on a style, often lobed, gen sticky or hairy.
Stipule – An appendage at the base of a petiole (leaf stem), sometimes in the form of a pair of tiny leaves, sometimes scale–like.
Strigose – Having stiff, straight, sharp, appressed hairs.
Style – Stem–like portion of the pistil connecting the ovary to the stigma.
Subtend – To occur immediately below.
Succulent – Juicy and fleshy, as the stem of a cactus or some dune plants.
Taxon (pl. taxa) – A taxanomic entity of any rank, e.g. genus, species, subspecies or variety.
Tendril – A slender coiling structure (generally a stem or stipule) by which climbing plants become attached to their supports.
Terminal – pertaining to or located at the tip of a stem or other structure.
Ternate – In threes, as a leaf consisting of 3 parts.
Thorn – A sharp-pointed stiff woody body derived from a modified branch.
Tomentose – Covered in dense, short, white or gray, woolly, generally matted hairs.
Truncated – As if cut off squarely at the end.
Tubercle – Small wart-like projection.
Twig – In woody plants, stem segment produced during the most recent or current growth period.
Umbel – Flower head with pedicels or flowers (if sessile) arising from a common point together as a unit.
Valve – One of the parts into which a capsule or legume splits.
Vestigial – Rudimentary; reduced to a trace or vestige of a formerly functional organ.
Whorl – A ring-like arrangement of flowers or leaves arising from a common point.
Wing – 1. A thin, flat extension or appendage of a surface or margin. 2. In the pea family, each of 2 lateral petals.