Glossary

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  • Abaxial(ly) -
    • The side away from the axis.
  • Acaulescent -
    • The leaves clustered at or near the base of the plant.
  • Achene -
    • A small, dry, 1-seeded indehiscent fruit.
  • Acuminate -
    • Gradually tapering to the apex.
  • Acute -
    • Tapering to the apex with straight sides.
  • Adaxial(ly) -
    • The side toward the axis.
  • Adnate/Adnation -
    • Fusion of unlike parts, as the stamens to the corolla.
  • Alkaline -
    • Having the properties of an alkali; a pH of more than 7.
  • Alluvium -
    • Clay, silt, sand, gravel, or similar detrital material deposited by running water.
  • Alternate -
    • Borne singly, not opposite
  • Amplexicaul -
    • Clasping the stem, as the base or stipules of some leaves.
  • Androgynous -
    • Having staminate flowers above the carpellate flowers.
  • 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 a stamen.
  • Anthesis -
    • Period when the flower is open.
  • Apetalous -
    • Having no petals.
  • Apex -
    • Uppermost point.
  • Apical notch -
    • Notch located at the apex or tip.
  • Apiculate -
    • Ending abruptly in a small, slender point.
  • Appressed -
    • Lying close to or flat against.
  • Arcuate -
    • Curved into an arch, like a bow.
  • Areole -
    • The point at which a cluster of spines arises; equivalent to a node (Cactaceae).
  • Argillaceous -
    • Clayey; of or pertaining to plants growing on clay soils.
  • Aristate -
    • Bearing an awn or bristle at the tip.
  • Arroyo -
    • The channel of an ephemeral stream in an arid region.
  • Auricle -
    • An ear or flap-like appendage at the summit of the leaf sheath in grasses.
  • Auriculate -
    • With auricles.
  • Awn -
    • A slender, bristle-like structure; the tips of glumes and lemmas on some grasses.
  • Axil -
    • Angle formed by a leaf with the stem to which it is attached.
  • Axillary -
    • In axil of leaf, branch, or other structure.
  • Banner -
    • The broad, erect, upper petal of the flower of legumes (Fabaceae).
  • Basal -
    • Leaves produced at ground level.
  • Basal rosette -
    • A dense radiating cluster of leaves positioned at, or arising from the base.
  • Basifixed -
    • Attached at the base, as anthers to the filament.
  • Beak -
    • A hard or firm point of projection.
  • Bi -
    • Prefix meaning two or twice.
  • Biennial -
    • A plant that lives for two growing seasons, usually flowering only in the second year.
  • Binate -
    • Borne in pairs.
  • Bisexual -
    • A flower having both stamens and pistils.
  • Blade -
    • Flat, expanded portion of leaf or petal.
  • Bract -
    • Reduced or modified leaf.
  • Bracteate –
    • With bracts.
  • Bractlet -
    • A secondary bract, usually smaller than the bracts.
  • Bristle -
    • Short, stiff, coarse hair or filament.
  • Bulb -
    • Underground bud covered with fleshy scales.
  • Bulbose -
    • Bulblike; with bulbs; of or pertaining to bulbs.
  • Caducous -
    • Falling off very early compared to similar structures in other plants.
  • Caespitose -
    • Growing in tufts or clumps.
  • Calcareous -
    • Referring to limestone or calcium-rich soils.
  • Callus -
    • Hardened base of the lemma in some grasses.
  • Calyx -
    • The collective name for sepals.
  • Campanulate -
    • Bell-shaped.
  • Capillary -
    • Thread-like.
  • Capitate -
    • Collected into a dense, head-like cluster.
  • Capsule -
    • A dry, dehiscent fruit made up of more than one carpel.
  • Carpel -
    • One of the female reproductive organs of a flower, i.e. a unit of the gynoecium, comprising an ovary (containing 1 to many ovules borne on a placenta) and with a usually terminal style tipped by the stigma.
  • Carpellate -
    • Having carpels.
  • Carr -
    • A wetland willow thicket.
  • Catkin -
    • A spike or spike-like inflorescence of unisexual flowers.
  • Caudex -
    • The persistent, often woody base of an otherwise herbaceous stem. Plural = caudices.
  • Cauline -
    • Leaves borne on the stem, above ground.
  • Ciliate -
    • With a marginal fringe of hairs.
  • Cinereous -
    • With grey or white pubescence that creates an ashy look.
  • Circumboreal -
    • Distributed around the high latitudes of the northern hemisphere in the boreal zone.
  • Clasping -
    • Leaf base partly or wholly surrounding the stem.
  • Clavate -
    • Club-shaped, gradually widening toward the apex.
  • Claw -
    • The narrow base or stalk to some petals.
  • Cleft -
    • Split about in the middle.
  • Cobwebby -
    • With the appearance of spider webbing, usually referring to very fine hairs.
  • Compound (leaf) -
    • A leaf divided into leaflets.
  • Congested -
    • Crowded, as in an inflorescence with many densely clustered flowers.
  • Connate -
    • United, usually by fusion or pressure in the bud.
  • Contracted -
    • Narrowed in a particular place.
  • Cordate -
    • Heart-shaped.
  • Coriaceous -
    • With a leathery texture.
  • Corolla -
    • Collective name for the petals.
  • Corymb -
    • A flat-topped or round-topped inflorescence, racemose, but with the lower pedicels longer than the upper.
  • Corymbiform -
    • An inflorescence with the general appearance, but not necessarily the structure, of a true corymb.
  • Corymbose -
    • Having flowers in corymbs. The term is sometimes used in the same sense as corymbiform.
  • Cristate -
    • With a terminal tuft or crest.
  • Cruciform -
    • Cross-shaped.
  • Culms -
    • The specialized stem of grasses, sedges and rushes.
  • Cuneate -
    • Wedge-shaped, triangular and tapering to a point at the base.
  • Cyme -
    • A flower cluster, usually opposite-branched, in its simplest form consisting of three flowers, the central or terminal one blooming first.
  • Deciduous -
    • Falling off; not permanent or evergreen.
  • Decumbent -
    • Prostrate except for the ascending tips of branches.
  • Decurrent -
    • Extending downward along stem or branch from the point of insertion.
  • Dehiscent -
    • Splitting open along regular lines, as in a fruit or anther.
  • Deltate -
    • See deltoid.
  • Deltoid -
    • Triangular.
  • Dendritic -
    • With a branching pattern similar to that in a tree, as in some hairs in the Cruciferae (Brassicaceae).
  • Dentate -
    • Toothed, with the teeth directed outward rather than forward.
  • Depauperate -
    • Stunted or poorly developed, usually due to adverse environmental conditions.
  • Didymous -
    • Developing or occurring in pairs; twin.
  • Dilated -
    • Expanded or widened.
  • Dioecious -
    • Having staminate and pistillate flowers on separate plants of a species.
  • Dimorphic -
    • Two forms.
  • Disjunct -
    • Separated from the main, continuous portion of a species’ range.
  • Disk flower -
    • The tubular flowers found at the center of the flower head of many members of the sunflower family.
  • Dissected -
    • Divided into many segments or lobes.
  • Divaricate -
    • Widely spreading.
  • Dorsal -
    • Pertaining to the back or outer surface.
  • Dorsiventral -
    • With an upper and lower side (flattened from the back rather than the sides).
  • Duff -
    • Organic matter on the forest floor.
  • Ebracteate -
    • Without bracts.
  • Echinate -
    • With prickles or spines.
  • Elliptical -
    • Shaped like an ellipse: widest in the center and the 2 ends equal.
  • Emarginate -
    • With a notch at the apex.
  • Endemic -
    • Restricted to a particular geographic region or soil type.
  • Entire -
    • Margins without teeth or lobes.
  • Ephemeral -
    • A plant that completes its life cycle very rapidly. In favorable environments ephemerals may germinate, bloom, and set seed several times during a single year.
  • Epicarp -
    • Outer layer of the fruit, the “skin”.
  • Erect -
    • Upright in relation to the ground.
  • Erose -
    • With the margin irregularly toothed, as if gnawed.
  • Evergreen -
    • Bearing green leaves or stems over the winter; not deciduous.
  • Exfoliate -
    • To come off in thin sheets.
  • Explanate -
    • Spread out flat, as opened anthers.
  • Exserted -
    • Projecting beyond a surrounding organ.
  • Farinose -
    • With a mealy or powdery covering of wax.
  • Fellfield -
    • Type of tundra that is thirty-five to fifty percent bare rock, with cushion plants, mosses, and lichens between.
  • Fen -
    • An area of wet peat that is typically alkaline due to ground water draining from surrounding calcareous rocks.
  • Fertile -
    • Capable of producing fruit or spores.
  • Fibrous (roots) -
    • Roots with several to many more or less equal branches; lacking a large central taproot.
  • Fistulose -
    • Hollow and cylindrical; tubular.
  • Filiform -
    • Thread-like.
  • Flaccid -
    • Soft and limp; drooping or hanging.
  • Flexuous -
    • Wavy or curved.
  • Floret -
    • A small flower, especially one in a dense cluster. Also used for a grass flower with its lemma and palea included.
  • Flower -
    • Reproductive structures of plants.
  • Follicle -
    • A type of dry fruit derived from a single pistil that splits open along only one suture line, as in milkweed pods.
  • Fornix -
    • A scale or gland-like protuberance in the flower tube, as in the Boraginaceae. Plural = fornices.
  • Frond -
    • Leaf of a fern.
  • Fruit -
    • The ripened, seed-containing reproductive structure of a plant.
  • Furcate -
    • Forked; often used in compounds, such as bifurcate or trifurcate.
  • Funiculus -
    • The stalk attaching the ovule or seed to the wall of the ovary (plural = funiculi); a structure of diagnostic value for Physaria spp. (Brassicaceae).
  • Gemma (pl. gemmae) -
    • A bud or bud-like structure, or cluster of cells which separate from the parent plant and propagate offspring plants.
  • Glabrate -
    • Almost glabrous.
  • Glabrous -
    • Without hairs.
  • Gland -
    • A depression or appendage which usually secretes a sticky fluid.
  • Glandular -
    • With organs which produce small droplets of secretion, often at tips of hairs.
  • Glaucescent -
    • Slightly glaucous.
  • Glaucous -
    • A whitish wax-like covering.
  • Globose -
    • Spherical.
  • Glume -
    • A bract at the base of a grass spikelet.
  • Gneiss -
    • Coarse-grained, banded metamorphic rock in which minerals are arranged in darker and lighter layers.
  • Graminoid -
    • Grass-like.
  • Granite -
    • Light-colored, coarse-grained igneous rock.
  • Granodiorite -
    • Granular intrusive quartz igneous rock, intermediate between granite and diorite; a quartzose diorite.
  • Gynaecandrous -
    • In Carex, pistillate flowers above staminate flowers.
  • Gynoecium -
    • Collective name for the pistils.
  • Gypsiferous -
    • Bearing gypsum (hydrous calcium sulfate).
  • Habitat -
    • The part of the environment where a plant grows.
  • Head -
    • A dense cluster of flowers, usually nearly spherical in outline. Individual flowers in the head are usually sessile or nearly so.
  • Helicoid -
    • Curled in the form of a spring or snail shell.
  • Herb -
    • A plant with no persistent woody stem above ground.
  • Herbaceous -
    • Non-woody; dying to the ground each year.
  • Hirsute -
    • With coarse, straight hairs.
  • Hispid -
    • Clothed with stiff bristles or bristle-like hairs, usually stiff enough to penetrate the skin.
  • Homostylous (homostylic) -
    • With styles of more or less constant length in flowers of the same species.
  • Hood -
    • Erect to spreading petaloid blade with incurved margins (Asclepiadaceae).
  • Hummock -
    • Small mound.
  • Hyaline -
    • Transparent or translucent.
  • Hypanthium -
    • Cup or tube formed by the fused bases of the stamens, petals, and sepals.
  • Igneous -
    • Rock that was crystallized from a magma.
  • Imbricate -
    • Overlapping like shingles.
  • Incised -
    • Cut sharply and usually irregularly with sharp sinuses.
  • Incurved -
    • Curved toward the axis or attachment.
  • Indehiscent -
    • Not splitting open at maturity.
  • Indusium -
    • A membranous flap covering the sorus of ferns. Plural = indusia.
  • Inferior -
    • Located beneath or lower than another structure, as in the ovary of a flower located beneath the sepals and petals.
  • 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.
  • Intermittent -
    • Not continuous.
  • Internode -
    • Portion of a stem or other structure between 2 nodes.
  • Involucel -
    • A small involucre; a secondary involucre, as in the bracts of the secondary umbels in the Umbelliferae (Apiaceae).
  • Involucre -
    • A whorl of bracts located beneath a flower cluster, as in the heads of members of the sunflower family (Asteraceae, Polygonaceae).
  • Involute -
    • Having edges rolled inward, like a scroll, toward the midnerve on the upper surface.
  • Keel -
    • A projecting central rib or dorsal ridge, like the keel of a boat.
  • Krummholtz -
    • Literally crooked forest; the low wind-contorted forest at timberline.
  • Laciniate -
    • Cut into narrow, irregular lobes or segments.
  • Lanceolate -
    • Lance-shaped; several times longer than wide, broadest toward the base and tapering to the apex.
  • Lateral -
    • Refers to the side, as opposed to dorsal.
  • Leaf -
    • Thin, usually green, expanded organ borne on a node of a stem.
  • Leaflet -
    • One of the divisions of a compound leaf.
  • Legume -
    • A dry, dehiscent fruit derived from a single carpel and usually opening along two lines of dehiscence, as a pea pod.
  • Lemma -
    • In grasses, the lower of two bracts enclosing the floret.
  • Ligule -
    • A hair-like or membranous projection up from the inside of a grass sheath at its junction with the blade.
  • Limb -
    • Expanded and spreading part above the throat, in a corolla with united petals.
  • Linear -
    • Narrow and flat with the sides parallel, like a grass leaf blade.
  • Lip -
    • The lowermost, often highly modified, petal of some flowers (such as orchids, mints, and penstemons).
  • Loam -
    • Class of soil texture composed of sand, silt, and clay, which produces a physical property intermediate between the extremes of the three components.
  • Lobe -
    • A division or segment of a structure, usually rounded in outline.
  • Locule -
    • Compartment or chamber of an ovary.
  • Lyrate -
    • Lyre-shaped; pinnatifid, with the terminal lobe large and rounded and the lower lobes much smaller.
  • Malpighian hair -
    • Straight hairs tapering to both free ends and attached near the middle; pick-shaped. (same as dolabriform)
  • Marcescent -
    • Persisting beyond a single season as dried parts.
  • Margin -
    • An edge, as in the edge of a leaf blade.
  • Mealy -
    • Soft, dry, and crumbly textured, as in certain fruits.
  • Membranaceous (membranous) -
    • Thin, soft, flexible, and more or less translucent, like a membrane.
  • Membranous -
    • Thin, soft, and pliable.
  • Midnerve-
    • The central nerve.
  • Midrib -
    • The main, central vein of a leaf, bract, scale, or petal.
  • Monocarpic -
    • Flowering and bearing fruit only once and then dying. The term may be applied to perennials, biennials, or annuals.
  • Monomorphic -
    • One form.
  • Monoecious -
    • Having the stamens and carpels in different flowers on the same plant.
  • Montane -
    • Relating to the biogeographical zone of relatively moist cool slopes below timberline dominated by large evergreen trees.
  • Mucro -
    • Minute and abrupt point at the apex.
  • Mucronate -
    • With a mucro.
  • Mucronulate -
    • Tipped with a very small mucro.
  • Muricate -
    • Rough with small, sharp projections or points.
  • Mycorrhiza (pl. mycorrhizae) -
    • A symbiotic relationship between a fungus and the root of a plant.
  • Node -
    • A joint or point of attachment for leaves or branches.
  • Nodulose -
    • With minute knobs or nodules.
  • Nutlet -
    • Hard, small, indehiscent, one-seeded fruit.
  • Ob -
    • A prefix implying the reverse.
  • 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.
  • Obpyramidal -
    • Inversely pyramidal, with the attachment at the narrower end.
  • Obpyriform -
    • Inversely pear shaped.
  • Obtuse -
    • Blunt or rounded at the apex.
  • Ochroleucous -
    • Off-white, buff.
  • 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.
  • Orbicular -
    • Circular in outline.
  • Ovary -
    • The part of the pistil of a flower that contains the ovules.
  • Ovate -
    • Egg-shaped, (two-dimensional) with the broadest end toward the base.
  • Ovoid -
    • Egg-shaped (three-dimensional).
  • Ovoid capsule -
    • Egg-shaped capsule.
  • Ovules -
    • Structure that develops into the seed.
  • Pagodaeform -
    • Shaped like a pagoda.
  • Palea -
    • The smaller of the two bracts (the other being the lemma) that enclose the stamens and pistil in a grass floret.
  • Pallid -
    • Deficient in color.
  • Palmate -
    • With leaflets, lobes, or veins arising from the same point at tip of petiole.
  • Pandurate -
    • Fiddle-shaped.
  • Panicle -
    • A compound inflorescence with two or more flowers on each branch.
  • Paniculate -
    • Having flowers in panicles.
  • Papilla(e) -
    • A minute epidermal wart(s).
  • Pappus -
    • An appendage at the apex of the ovary.
  • Partition -
    • Line separating the two halves of the fruit of a mustard (Brassicaceae).
  • Peat -
    • Highly organic soil often in bogs or fens.
  • 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 spiklet.
  • Peduncle -
    • The stalk of an inflorescence.
  • Pendant -
    • A structure that is allowed to hang free.
  • Pendulous -
    • Hanging downward.
  • Perennial -
    • A plant which lives for three or more years.
  • Perianth -
    • Collective term for the calyx and corolla of a flower.
  • Perigynium -
    • The inflated sac enclosing the ovary in species of Carex (Cyperaceae). Plural = perigynia.
  • Persistent -
    • Remaining attached after similar parts are normally dropped, after the function has been completed.
  • Petal -
    • The usually colored, individual components of the corolla of a flower; literally the leaves of a flower.
  • Petiolar -
    • Pertaining to the petiole; growing from the petiole.
  • Petiole -
    • The leaf stalk.
  • Petiolate -
    • Having a petiole.
  • Phyllary -
    • The involucral bract on the head of members of the sunflower family (Asteraceae).
  • Phyllode -
    • An expanded, leaf-like petiole lacking a true leaf blade.
  • Phyllopodic -
    • With the lowest leaves well developed, not reduced to scales.
  • Pilose -
    • Covered with long, soft hairs.
  • Pinna(e) -
    • One of the first or primary divisions of a pinnately compound leaf: usually used to describe ferns.
  • Pinnate -
    • Compound leaf with the leaflets on 2 opposite sides of an elongated axis.
  • Pinnately compound -
    • Division of a leaf blade into leaflets arranged on each side of a common leafstalk.
  • Pinnatifid -
    • Pinnately lobed, cleft or parted 1 ¦2 way to the midrib or more.
  • Pinnatisect -
    • Pinnately dissected.
  • Pinnule -
    • A secondary division of a fern frond.
  • Pistil -
    • The seed-producing organ, consisting of a stigma and ovary with a style between.
  • Pistillate -
    • A flower which lacks well-developed, functional stamens.
  • Placenta -
    • Any part of the interior of an ovary that bears ovules.
  • Playa -
    • An inland drainage basin, surrounded by sheets of alkaline or saline crust and containing a shallow, often ephemeral lake.
  • Plumose -
    • Hairs with side hairs along the main axis like the plume of a feather.
  • Pod -
    • Any dry, dehiscent fruit, such as that of many members of the pea family (Fabaceae).
  • Pollinium (pl. pollinia) -
    • A mass of waxy pollen grains transported as a unit in many members of the Orchidaceae and Asclepiadaceae.
  • 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).
  • Puberulent -
    • With very short hairs.
  • Pubescence -
    • Hair on various parts of the plant.
  • Pubescent -
    • Having hairs.
  • Punctate -
    • Dotted with pits or with translucent, sunken glands or with colored dots.
  • Puncticulate -
    • Minutely punctate.
  • Pungent -
    • Sharp-pointed, prickly to touch.
  • Pustulate -
    • With wart-like elevations; hairs with an expanded or wart- like base.
  • Pustulose -
    • Hirsute, with basally swollen hairs.
  • Raceme -
    • An elongate inflorescence made up of stalked flowers attached directly to the main axis.
  • Rachis -
    • The central elongated axis to an inflorescence or a compound leaf.
  • Ray flower -
    • 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).
  • Receptacle -
    • The enlarged tip of the flowering stem that bears all or most of the flower parts.
  • Recurved -
    • Curved downward or backwards.
  • Reflexed -
    • Abruptly bent downward or back.
  • Replum -
    • Internal membranous partition dividing the fruit of mustards into halves.
  • Reticulate -
    • In the form of a network as in leaf veins.
  • Retrorse -
    • Directed backward or downward.
  • Retuse -
    • With a shallow notch in a round or blunt apex.
  • Revolute -
    • Rolled backward from the margin to the lower side.
  • Rhizomatous -
    • Bearing rhizomes.
  • Rhizomes -
    • Prostrate stem growing beneath the ground surface, usually rooting at the nodes.
  • Rhombic -
    • Diamond-shaped.
  • 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.
  • Rugose -
    • Wrinkled.
  • Rugulose -
    • Slightly wrinkled.
  • Runcinate -
    • Sharply pinnatifid or cleft, the segments directed downward.
  • Saccate -
    • Shaped like a pouch or bag.
  • Sagittate -
    • Arrow shaped.
  • Saline -
    • Consisting of or containing salt.
  • 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 pistillate flowers.
  • Scape -
    • A leafless flower stalk.
  • Scar -
    • A mark left on a stem, branch, or nutlet.
  • Scarious -
    • Thin, dry, and membranous in texture, not green.
  • Schist -
    • Medium to coarse-grained metamorphic rock composed of parallel layers which are often waxy or flaky.
  • Scorpiod -
    • Shaped like a scorpion’s tail, as in some coiled cymes; a determinate inflorescence with a zigzag rachis.
  • Scree -
    • Accumulation of rocky debris lying on a slope or at the base of a hill.
  • Secund -
    • Oriented on one side of an axis, as in fruits or flowers all being on one side of a stem.
  • Sedimentary -
    • Rock formed by the deposition and compression of mineral and rock particles.
  • Seleniferous -
    • Containing or yielding selenium.
  • Selenium -
    • A non-metallic element that is found with sulfur in various ores; often selectively concentrated by certain legumes.
  • Sepals -
    • A segment of the calyx.
  • Septate -
    • Divided by one or more partitions (septa).
  • Septum (pl. septa) -
    • A partition, as the partitions separating the locules of an ovary.
  • Serrate -
    • With sharp teeth pointed forward.
  • Sessile -
    • Lacking a stalk.
  • Shale -
    • Fine-grained sedimentary rock, usually composed of clays.
  • Sheath -
    • The lower part of the leaf that enfolds the stem in grasses, sedges, and rushes.
  • Shoot -
    • New growth.
  • Shrub -
    • A woody plant with several equally large stems from the base, usually less than 4.5 m tall.
  • Sigmoid -
    • Curved in two directions like the letter S.
  • Silicle -
    • A dry, dehiscent fruit of the Cruciferae (Brassicaceae), typically less than twice as long as wide, with two valves separating from the persistent placentae and septum (replum).
  • 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.
  • Sinuate -
    • Wavy-margined.
  • Solifluction -
    • Downhill movement of unconsolidated materials that have become saturated with water.
  • Solitary -
    • Occurring singly, not as part of a group or cluster.
  • Sorus -
    • A cluster of sporangia (structure containing spores). Plural = sori.
  • Spadix -
    • A spike with small flowers crowded on a thickened axis.
  • Spathe -
    • Large bract sheathing or enclosing an inflorescence.
  • Spatulate -
    • Oblong, but narrowed at base.
  • Spicate -
    • Arranged in a spike; spike-like.
  • 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.
  • Spinescent -
    • Bearing a spine or ending in a spine-like sharp point.
  • Sporangium -
    • Spore-bearing case. 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.
  • Spreading -
    • Diverging at nearly a right angle from a structure; nearly prostrate.
  • Spur -
    • A tubular or sac-shaped extension of a petal or sepal.
  • Stalk -
    • Main stem of a herbaceous plant.
  • Stamen -
    • The pollen-producing structures of a flower; the “male” part of a flower.
  • Staminate -
    • With stamens, but lacking a pistil; “male”.
  • Staminode -
    • A sterile stamen or any structure lacking an anther but corresponding to a stamen.
  • Stellate -
    • Star-like or star-shaped; like an asterisk.
  • Sterile -
    • Non-fertile; structure lacking reproductive parts or abilities.
  • Stigma -
    • The surface of the pistil on which pollen grains land.
  • Stipe -
    • Stalk.
  • Stipitate -
    • Having a stalk (stipe).
  • 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.
  • Stoloniferous -
    • Bearing stolons.
  • Strigillose -
    • Diminutive of strigose. Also, strigulose.
  • Strigose -
    • Beset with sharp-pointed, straight appressed hairs.
  • Style -
    • The portion of the pistil between the ovary and the stigma.
  • Sub -
    • Prefix which refers to under or below.
  • Subalpine -
    • Region lying below the alpine.
  • Subapical -
    • Near the apex.
  • Submarginate -
    • Near the margin.
  • Suborbiculate -
    • Almost orbicular in shape.
  • Subpandurate -
    • Almost fiddle-shaped.
  • Subsessile -
    • Nearly sessile.
  • Subshrub -
    • A suffrutescent perennial plant; a small shrub.
  • Substrate -
    • Any object or material upon which an organism grows or to which an organism is attached.
  • Subulate -
    • Awl shaped.
  • Subtend -
    • To be situated immediately below, as in bracts beneath a flower.
  • Succulent -
    • Fleshy and full of juice.
  • Suffrutescent -
    • Somewhat shrubby; slightly woody at the base.
  • Sympatric -
    • Applied to species that occupy similar habitats or whose habitats invariably overlap.
  • Talus -
    • Sloping mass of coarse rock fragments accumulated at the foot of a cliff or slope.
  • Taproot -
    • The primary root from which secondary (smaller, lateral) roots arise.
  • Terminal -
    • Located at the tip of a structure.
  • Ternate -
    • In threes or with three parts.
  • Ternately compound -
    • Divided into threes, as in a leaf consisting of three leaflets.
  • Terete -
    • Cylindrical; circular in cross-section.
  • Tooth -
    • Any small, marginal lobe, usually on the edge of a leaf blade.
  • Tomentose -
    • With a dense wool-like covering of matted, intertangled hairs of medium length.
  • Tortuous -
    • Bent or twisted in various directions.
  • Torulose -
    • Alternately swollen and constricted, a condition often found in the fruit of certain mustards (Brassicaceae).
  • Translucent -
    • Transmitting light, but causing sufficient diffusion to eliminate perception of distinct images.
  • Tri -
    • Prefix meaning three or thrice.
  • Trichome -
    • The specific term for any type of plant hair.
  • Trifoliate -
    • Having three leaves.
  • Trifoliolate -
    • Having three leaflets.
  • Triforked -
    • Divided into three branches, as in hairs that are divided near their tip into three separate branches.
  • Trigonous -
    • Three-angled, three-sided (usually refers to achenes).
  • Tubercle -
    • A small expanded structure, such as the base of the style in some sedges, or very large papillae on fruits.
  • Tuberculate -
    • Having tubercles.
  • Tufted -
    • A close-growing cluster of stems, as in certain bunchgrasses, sedges, and mat-forming herbs.
  • Turbinate -
    • Top-shaped.
  • Turion -
    • A small shoot which often over-winters, as in Asparagus and in some species of Epilobium.
  • Tussock -
    • A compact, densely tufted growth form of some grasses and sedges.
  • Twice-pinnate -
    • Two divisions of a leaf blade into leaflets arranged on each side of a common leafstalk.
  • Twig -
    • The current year’s growth of a 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.
  • Umbo -
    • A blunt or rounded protuberance, as on the ends of the scales of some pine cones.
  • Umbonate -
    • Possessing an umbo.
  • Unilocular -
    • With one locule.
  • Uniseriate -
    • Arranged in a single row or series.
  • 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.
  • Villous -
    • Clothed with long, soft hairs, often without special orientation.
  • Viscid -
    • Sticky; with sticky exudates.
  • Whorled -
    • Three or more leaves or branches attached at the same level on stem.
  • Wing -
    • A thin, often dry or leaf-like extension bordering a structure; in some members of the pea family (Fabaceae), the two lateral petals of the flower; or a fruit as in Onagraceae or Cyperaceae.
  • Woolly -
    • With long, interwoven hairs.