Jepson eFlora Glossary

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Citation for the whole project: Jepson Flora Project (eds.) 2025. Jepson eFlora, https://ucjeps.berkeley.edu/eflora/ [accessed on 18th May 2025]

One of the main goals of the Jepson eFlora is to facilitate plant identification, which often relies on extremely subtle differences in plant characters. The terminology used in the Jepson eFlora is constrained to make the work accessible to a broad audience. All users are encouraged to routinely consult the glossary, and beginners are encouraged to study the glossary, as a way to acquire the basic botanical knowledge needed to identify plants.

• abaxial.
  Side or surface of a structure away from the axis distal to the point at which the structure is borne (e.g., lower surface of a leaf, outer surface of a petal). (see adaxial)
• abundant.
  Very likely present in appropriate habitats, sometimes forming dense stands (see common, rare, uncommon)
• achene.
  Dry, indehiscent, 1-seeded fruit from a 1-chambered ovary in which the fruit wall is free from the seed, sometimes winged; often appearing to be a naked seed. 1-seeded dry fruit derived from an inferior ovary of > 1 carpel (e.g., Asteraceae, Dipsacaceae, Valerianaceae) is sometimes called a cypsela.
• acid (acidic).
  Soil or water with a low pH, often found in habitats such as coniferous forests and bogs where decomposition of plant remains liberates an excess of hydrogen ions.
• acroscopic.
  In ferns, facing or directed toward the tip of the leaf (e.g., on any pinna, acroscopic pinnules are those on the side closest to the leaf tip). (see basiscopic, distal)
• acuminate.
  Having a long-tapered, sharp tip, the sides concave. (see acute, attenuate, awl-like)
• acute.
  Having a short-tapered, sharp tip, the sides convex or straight and converging at less than a right angle. (see acuminate, attenuate, awl-like, obtuse)
• adaxial.
  Side or surface of a structure toward the axis distal to the point at which the structure is borne (e.g., upper surface of a leaf, inner surface of a petal). (see abaxial)
• adherent.
  Sticking to and sometimes appearing fused to another part of like or unlike kind, but separable from it, such as "perianth adherent to fruit". (see appressed, fused)
• adventitious.
  Arising at unusual times or places, such as roots on aerial stems.
• aggressive.
  Growing or spreading rapidly or invasively, outcompeting other plants, difficult to control.
• alien.
  Not native; introduced purposely or accidentally into an area. (see native, naturalized, ruderal, waif)
• alkali, alkaline.
  Soil or water with a high pH (i.e., basic), often found in areas where evaporation concentrates dissolved solutes.
• alkali sink.
  Basin area in region of interior drainage characterized by soils with high salinity and high pH.
• alluvial.
  Pertaining to sediments deposited by flowing water.
• alluvial fan.
  Fan-shaped deposit of rocks, gravel, and finer sediments, in California generally on lower slopes of mountains.
• alpine.
  Pertaining to the vegetational/altitudinal zone above timberline; zone above the subalpine.
• alternate.
  1. Arranged singly, often spirally, along an axis (e.g., one leaf per node). (see opposite, whorled) 2. Occurring in different ranks, appearing to be between, not directly above or below, as "stamens alternate petals". (see rank)
• angiosperm.
  Plant that bears flowers (hence, "flowering plant"), in which "vesseled seeds" (hence, angio-sperm) are enclosed in an ovary; woody to herbaceous.
• annual.
  Completing life cycle (germination through death) in one year or growing season, generally non-woody. (see biennial, herb, perennial)
• anther.
  Pollen-bearing portion of a stamen, including one, two, or four pollen sacs. (see filament)
• apogamous.
  Forming a sporophyte (the generation in a vascular plant life cycle that is conspicuous, 2n, and produces spores, which give rise to gametophytes) from a gametophyte (the generation in a vascular plant life cycle that is inconspicuous, n, and produces sperms and eggs, which usually unite in fertilization to give rise to sporophytes) by direct, asexual development, rather than by fertilization of eggs by sperms.
• appressed.
  Parallel or nearly parallel to and often in contact with surface of origin; used to describe the disposition of hairs, leaves, pedicels, etc. (see adherent, fused)
• aquatic.
  Growing under, in, or on water (generally fresh; if brackish, saline, or marine, so indicated), whether rooted in bottom or floating, and including plants with parts of shoots submersed but with other parts above water (e.g., Potamogeton gramineus); excluding plants of seeps or wet rocks. (see emersed, submersed)
• areole.
  1. In Cactaceae, a well-defined, axillary area (short shoot) generally bearing one to many spines and other, shorter structures (e.g., Ferocactus cylindraceus glands, Opuntia glochids). 2. In general, each of many areas defined by smallest veins on a leaf.
• aril.
  Fleshy, corky, or bony appendage arising at or near the point of seed attachment, sometimes completely covering the seed.
• armed.
  Bearing prickles, spines, or thorns.
• ascending.
  Curving or angling upward from base, or about 30—60° less than vertical or away from axis of attachment. (see decumbent, erect)
• asymmetric.
  Not divisible into identical or mirror-image halves. (see bilateral, biradial, radial)
• attenuate.
  Having a long-tapered, sharp tip. (see acuminate, acute, awl-like)
• auricle.
  In Poaceae, a structure, often lanceolate, projecting from both margins of the leaf lateral to the ligule. (see ligule)
• awl-like.
  Narrow throughout, but broader at the base and tapered to a sharp tip. (see acuminate, acute, attenuate)
• awn.
  1. Bristle-like appendage or elongation, generally terminal. 2. Stiff, needle-like pappus element in Asteraceae.
• axil.
  Distal, adaxial angle between an appendage or branch and a main axis (e.g., between leaf and stem, or between lateral vein and midrib on a leaf).
• axile.
  Pertaining to an axis, as of a placenta along the central axis in a compound ovary with more than one chamber.
• axillary.
  Pertaining to or within an axil, especially a leaf axil.
• axis (axes).
  Line of direction, growth, or extension; structure occupying such a position (e.g., the main stem of a plant or inflorescence, the midrib of a leaf).


• banner.
  Uppermost, often largest petal of many members of Fabaceae.
• bar.
  Mound-like temporary deposit of sand or gravel in the channel or mouth of a waterway.
• barbed.
  Having sharp, normally downward- or backward-pointing projections. Said of an awn, bristle, or other structure.
• bark.
  Tough tissue (including phloem) covering the wood (hardened xylem) of subshrubs, shrubs, trees, and some vines. (see wood)
• barren.
  Area in which vegetation is sparse due to harsh or limiting growing conditions, such as those associated with shallow, infertile, rocky soil.
• basal.
  At or near the base of a plant or plant part. Especially said of leaves clustered near the ground or of a placenta confined to the base of an ovary.
• basiscopic.
  In ferns, facing or directed toward the base of the leaf (e.g., on any pinna, basiscopic pinnules are those on the side closest to the leaf base). (see acroscopic, proximal)
• beak.
  Generally distal or terminal, narrowed, generally sterile part of fruit or surrounding structures (e.g., Ambrosia bur, Carex perigynium).
• bell-shaped.
  Widening more or less abruptly at the base and then generally more gradually toward the tip. (see funnel-shaped, rotate, salverform, urn-shaped)
• berry.
  Fleshy, indehiscent fruit in which the seeds are generally more than 1 and are not encased in a stone (e.g., Solanum americanum). (see drupe, pome)
• biennial.
  Completing life cycle (germination through death) in two years or growing seasons (generally flowering only in the second), non-woody (at least above ground), often with a rosette the first growing season. (see annual, herb, perennial)
• bilateral.
  Divisible into mirror-image halves in only one way. (see asymmetric, biradial, radial)
• biradial.
  Divisible into mirror-image halves in two ways; isobilateral. (see asymmetric, bilateral, radial)
• bisexual.
  Both male and female reproductive parts occurring and functional in the same plant or structure (e.g., flower, spikelet, inflorescence). (see unisexual, pistillate, staminate, dioecious, monoecious)
• blade.
  Expanded portion of a leaf, petal, or other structure, generally flat but sometimes rolled, cylindric, wavy, or cupped.
• brackish.
  Somewhat salty, generally a mixture of saline and fresh water.
• bract.
  1. Generally reduced, leaf- or scale-like structure subtending a branch, cone scale, inflorescence (infl bract), or sessile flower or pedicel (fl bract). 2. Generally reduced, leaf- or scale-like structure on a peduncle or scape that may or may not subtend another structure. (see bractlet)
• bractlet.
  1. Relatively small, generally secondary bract within an inflorescence. 2. Bract-like structure on a pedicel that may or may not subtend another structure. (see bract)
• bristle.
  1. Relatively large, generally stiff, more or less straight hair (e.g., Navarretia breweri). 2. In Asteraceae, fine, cylindric or minutely flattened pappus element (e.g., Calycoseris parryi) or epidermal outgrowth on the receptacle (e.g., Centaurea solstitialis).
• bud.
  1. Incompletely developed, more or less embryonic shoot, usually covered with bud scales. 2. Unopened flower, often protected by sepals.
• bulb.
  Short underground stem and the fleshy leaves or leaf bases attached to and surrounding it (e.g., an onion). (see stem, corm, caudex, tuber)
• bulblet.
  1. Small bulb generally produced at the base of a bulb. 2. Any small, bulb-like structure that propagates a plant, often in a leaf or bract axil.
• bur.
  Fruit or fruiting inflorescence with awns or bristles, often barbed (e.g., Xanthium strumarium).


• callus.
  1. In some Poaceae, enlarged or projected hard base of floret; sometimes hairy or sharp-pointed. (see floret) 2. Firm protuberance.
• calyx (calyces).
  Collective term for sepals; outermost or lowermost whorl of flower parts, generally green and enclosing remainder of flower in bud. Sometimes indistinguishable from corolla.
• canescent.
  Covered with dense, fine, generally grayish white hairs (e.g., Phoenicaulis cheiranthoides leaf).
• capsule.
  Dry fruit from compound pistil, nearly always dehiscent (irregularly or by pores, slits, or lines of separation). (see circumscissile, loculicidal, septicidal)
• carpel.
  Basic female structure of a flower, evolved from a fertile leaf. Carpels are free or variously fused into a compound pistil, the number of carpels then often equal to the number of stigmas, styles, or chambers of the ovary. (see pistil)
• cartilaginous.
  Thickened, usually whitish, sometimes flexible; in ferns, applied especially to margins of blades.
• catkin.
  Spike or spike-like (e.g., Alnus) inflorescence of unisexual flowers with inconspicuous perianths (generally wind-pollinated), usually pendent and often with conspicuous bracts.
• caudex (caudices).
  Generally short, sometimes woody, more or less vertical stem of a perennial, at or beneath ground level. (see stem, bulb, corm, tuber)
• cauline.
  Pertaining to structures, especially leaves, borne along (i.e., not confined to the base of) an elongate, above-ground stem; not basal.
• centimeter.
  One-hundredth of a meter; 10 millimeters (abbreviation: cm).
• cespitose.
  Having a densely clumped, tufted, matted, or cushion-like growth form.
• chamber.
  Compartment or cavity within an ovary, capsule, or other hollow structure.
• chaparral.
  Vegetation characterized by mostly evergreen shrubs with thick, leathery leaves and stiff branches.
• ciliate.
  Having generally straight, conspicuous hairs (cilia) along margins or edges.
• circumboreal.
  Occurring around the world at northern latitudes.
• circumscissile.
  Dehiscence, usually of a fruit (capsule), by a transverse line, the top coming off as a lid. (see loculicidal, septicidal)
• claw.
  Stalk-like base of some free or nearly free sepals or petals. (see limb)
• cleistogamous.
  Bud-like, unopening flowers that are generally self-fertilized.
• clone.
  Genetically identical individuals resulting from asexual reproduction (fragmentation of rhizomes or stolons, budding, etc.); often used for an apparent population, the members of which are or were connected (e.g., aspens, cattails, duckweeds, sumacs).
• closed-cone conifer forest or woodland.
  Vegetation characterized by species of Pinus or Hesperocyparis in which the seed cones persist unopened on the branches for extended periods of time.
• coastal scrub.
  Coastal vegetation characterized by shrubs with flexible branches (e.g., Baccharis pilularis, Artemisia californica).
• coastal strand.
  Beach and foredune habitat, characterized by sandy soils, strong winds, salt spray, and wave action.
• collar.
  1. In Poaceae, the abaxial junction of leaf sheath and blade. 2. Raised, inflated, or wing-like, encircling projection (e.g., seeds of Delphinium luteum, D. nudicaule).
• column.
  Structure at the center of an orchid flower formed by fusion of stamen(s) and style.
• common.
  Likely present in appropriate habitats. (see abundant, rare, uncommon)
• compound.
  1. Composed of two or more parts, as a compound leaf composed of leaflets (see compound leaf) or a compound pistil composed of fused or partly fused carpels. 2. Repeating a structural pattern (a compound umbel is an umbel of umbels). (see simple)
• compound leaf.
  Leaf divided into distinct parts. In a 1-compound leaf, the blade is divided into primary leaflets connected by an axis but no blade material, in a 2-compound leaf, the primary leaflets are so divided into secondary leaflets, etc. (see palmate, pinnate, lobed, dissected)
• compressed.
  Flattened side-to-side (laterally compressed) or front-to-back. (see depressed)
• concave.
  Hollowed or indented, as the interior of a curved surface. (see convex)
• cone.
  Reproductive structure composed of an axis, scales, and sometimes bracts. 1. Non-woody structure producing spores (e.g., clubmosses, horsetails) or pollen (e.g., male cone of conifers). 2. Generally woody structure producing seeds (e.g., female cones of most conifers).
• conic.
  Three-dimensional, defined by a wide, more or less round base, the sides evenly tapered to a narrow tip.
• conifer forest.
  Vegetation characterized by trees belonging to various species of conifers (e.g., firs, pines, redwoods).
• continuous.
  Having parts spaced evenly and without interruption, not clumped; pertaining especially to inflorescences in which the flowers are evenly spaced. (see interrupted)
• convex.
  Rounded outward, as the exterior of a curved surface. (see concave)
• cordate.
  Heart-shaped; often pertaining to a leaf in which the blade base on both sides of the petiole is rounded and convex. (see reniform)
• corm.
  Short, thick, unbranched, underground stem often surrounded by dry (not fleshy) leaves or leaf bases (e.g., Muilla maritima). (see bulb, stem)
• corolla.
  Collective term for petals; whorl of flower parts immediately inside or above calyx, often large and brightly colored. Sometimes indistinguishable from calyx.
• costa (costae).
  In ferns, primary axis of a pinna.
• cotyledon.
  Seed-leaf; a modified leaf present in the seed, often functioning for food storage. Persistent in some annuals and of aid in their identification (e.g., Lupinus microcarpus).
• crenate.
  Pertaining to margins with shallow, rounded teeth, between which are usually acute sinuses (i.e., scalloped).
• cylindric.
  Elongate, with parallel sides and, at any point, round in transverse section.
• cyme.
  1. In flowering plants excluding Asteraceae and some other groups, a branched inflorescence in which the central or uppermost flower opens before the peripheral or lowermost flowers on any axis. (see panicle) 2. In Asteraceae and some other groups, a cyme-like inflorescence is one in which the central or uppermost inflorescence units (e.g., heads in Asteraceae, umbels enclosed by involucres in Eriogonum), instead of individual flowers, develop and mature before the peripheral or lowermost inflorescence units on any axis.
• cypsela.
  (see achene)


• deciduous.
  Falling off naturally. 1. Pertaining to leaves that all fall seasonally, or to plants that are seasonally leafless. (see evergreen) 2. Pertaining to structures, such as hairs or flower parts, that fall early or readily.
• decimeter.
  One-tenth of a meter; 10 centimeters (abbreviation: dm).
• decumbent.
  Lying mostly flat on the ground but with tips curving up. (see ascending, prostrate)
• decurrent.
  Pertaining to a wing-like or ridge-like extension basal to the apparent or actual point of attachment, particularly a leaf base that appears to continue onto the stem.
• dehiscent.
  Opening at maturity to release contents; usually pertaining to anthers or fruits. (see indehiscent)
• deltate.
  More or less equilaterally triangular, with the corners rounded or not.
• dense.
  Congested or compact; especially pertaining to the disposition of flowers in an inflorescence. (see open)
• dentate.
  Having margins with sharp, relatively coarse teeth pointing outward, not tipward. (see serrate)
• depressed.
  Flattened from above and below, or with the center lower than the margins. (see compressed)
• desert.
  Region and associated communities characterized by low and irregular precipitation and prolonged periods of drought.
• desert woodland.
  Vegetation in desert region or on slopes of adjacent mountains characterized by small, drought-tolerant trees; may be classified by characteristic species (e.g., Joshua tree woodland characterized by Yucca brevifolia, pinyon/juniper woodland characterized by Pinus monophylla and Juniperus).
• digitate.
  In Poaceae, pertaining to an inflorescence of two or more spike-like branches attached at the same point at the apex of the inflorescence stalk.
• dioecious.
  Pertaining to a taxon in which individuals produce either male or female reproductive structures, and do not produce bisexual reproductive structures (e.g., Salix laevigata). (see monoecious)
• diploid.
  Having two sets of chromosomes (maternal and paternal); 2n. (see haploid, n, polyploid)
• disciform head.
  In Asteraceae, a head composed of disk flowers and marginal pistillate (or sterile) flowers with minute or missing rays, superficially similar to discoid head. (see discoid head, liguliflorous head, radiant head, radiate head)
• discoid head.
  In Asteraceae, a head composed entirely of disk flowers. (see disciform head, liguliflorous head, radiant head, radiate head)
• disk.
  1. Fleshy, often nectar-secreting structure near (often surrounding) an ovary or style base. 2. In Asteraceae, the aggregation of disk flowers in the center of a discoid or radiate head.
• disk flower.
  In Asteraceae, a generally bisexual (occasionally staminate or sterile, never pistillate), generally radial flower with a 5- (rarely 4-) lobed corolla; appearing without other flower types (in discoid head), or with marginal flowers of a different type (in radiate, radiant, or disciform heads). (see ligulate flower, ray flower)
• dissected.
  Deeply, often sharply cut but not compound; usually pertaining to leaves (e.g., Cymopterus deserticola). (see compound leaf, leaflet, lobe, segment)
• distal.
  Farther away from the base, origin, or point of attachment, or closer to the edge or tip. (see proximal)
• drupe.
  Fleshy or pulpy, indehiscent, superficially berry-like fruit in which 1 seed is encased in a stone (as in cherries; e.g., Prunus emarginata fruit), or more than 1 seed is encased in an equal number of free or variously fused stones (as in manzanitas). (see berry, nut, pome, stone)
• dune.
  Hill or ridge of sand formed by the wind.


• e-.
  Prefix meaning without, lacking (e.g., in Asteraceae, an epaleate receptacle is one that lacks paleae).
• ellipsoid.
  In the shape of a flattened or elongated sphere, widest at the middle and tapered equally to both ends, as a fruit; wider than linear. (see elliptic, linear, oblong)
• elliptic.
  In the shape of a flattened or elongated circle, widest at the middle and tapered equally to both ends, as a leaf; wider than linear. (see ellipsoid, linear, oblong)
• emergent.
  Pertaining to a plant normally rooted underwater and extending above the water surface, or to a part of such a plant normally held above the water surface (e.g., Persicaria amphibia). (see aquatic, submersed)
• endemic.
  Native to and restricted to a defined geographic area.
• entire.
  Having margins that are continuous and smooth (i.e., without teeth, lobes, etc.).
• ephemeral.
  Lasting a short time. 1. Pertaining to individual plants, completing the life cycle (germination through death) or growth cycle in much less than one year. 2. Pertaining to plant parts, falling early or remaining functional for a relatively short time (e.g., less than a day for flower parts).
• epidermis.
  Outermost cell layer (or layers) of non-woody plant parts.
• epipetalous.
  Pertaining to stamens that are fused to the petals to various extents and therefore appear to arise from them.
• erect.
  Upright; vertically oriented. (see ascending)
• estuarine.
  Pertaining to aquatic habitats where freshwater from streams mixes with sea water in a protected area, resulting in a gradation of brackish waters with varying degrees of salinity.
• evergreen.
  Never leafless; usually pertaining to leaves that remain green and on the plant for more than one season, and that do not all fall seasonally, or to plants that are never leafless. (see deciduous)
• exceeding.
  Surpassing tipward, due to relative orientation or length of the structures involved (e.g., lateral branches exceeding inflorescences; hoods exceeded by anther head in Asclepias californica; hoods slightly exceeding anther head in Asclepias erosa). (see exserted)
• exserted.
  Protruding out of surrounding structure(s) (e.g., stamens exserted from corolla). (see exceeding, included)
• extant.
  Currently existing or surviving somewhere. (see extinct, extirpated)
• extinct.
  No longer existing or surviving anywhere. (see extant, extirpated)
• extirpated.
  No longer existing or surviving in a defined geographic area, as either a direct or indirect result of human activity. (see extant, extinct)
• exudate.
  Material discharged (exuded) from a plant, often with characteristic odor, color, or texture (e.g., sticky, gummy, slippery).


• false indusium (false indusia).
  In many ferns, but especially Pteridaceae and Dennstaedtiaceae, a reflexed or rolled under, often modified leaf blade margin that covers a sorus and protects the young sporangia; also called a marginal indusium. (see indusium)
• fertile.
  Reproductively functional; pertaining to a plant or plant part that produces or is associated with the production of functional spores, pollen, ovules, or seeds (e.g., fertile leaf, fertile stamen, fertile flower, fertile floret). (see sterile)
• fibrous.
  1. Pertaining to structures that are composed at least in part of more or less thread-like but usually tough elements (e.g., Yucca leaves). 2. Pertaining to a root system composed of many roots similar in length and thickness (e.g., grass roots). (see taproot)
• filament.
  Anther-stalk portion of a stamen, often thread-like.
• fleshy.
  Thick and juicy; succulent (e.g., Sesuvium verrucosum).
• floret.
  In Poaceae, a single flower and its immediately subtending bracts (lemma and generally palea, the lemma subtending the palea when the latter is present); in a sterile floret, the flower and sometimes palea are rudimentary or absent. (see glume, lemma, palea, spikelet)
• flower.
  Primary reproductive structure of angiosperms, with stamens and/or carpels and usually a perianth of sepals and/or petals. (see stamen, carpel, perianth, sepal, petal)
• follicle.
  Dry fruit from a simple pistil, dehiscent on generally only one side, along a single suture. A single flower may develop into a simple fruit of 1 follicle or an aggregate fruit of several follicles. (see capsule, legume)
• foothill.
  Slope at the base of a mountain; especially applied to such features in CA-FP.
• foothill woodland.
  Vegetation in foothills characterized by small- to medium-sized trees, composed of one or more species of Quercus, often mixed with Pinus sabiniana and/or Aesculus californica.
• forest.
  Vegetation characterized by closely spaced ± tall trees; with more canopy cover than a woodland (canopies often overlap).
• forked.
  Pertaining to a hair or other structure that branches into two parts. (see stellate)
• free.
  Neither fused to nor adherent to other parts; distinct, separate.
• free-central.
  Pertaining to a placenta along the central axis in a compound ovary with only one chamber. (see axile, basal, parietal)
• fringed.
  Having ragged or finely cut margins.
• fruit.
  Ovary or ovaries and sometimes associated structures after ovule fertilization (i.e., seed initiation). A simple fruit develops from one ovary (e.g., cherry, apple, the latter derived largely from the hypanthium); aggregate and multiple fruits develop from ovaries of one and more than one flower, respectively, that remain distinct yet held together as a unit (e.g., a strawberry is an aggregate fruit of achenes held together by a juicy, red flower receptacle; a fig is a multiple fruit of achenes surrounded by a fleshy inflorescence receptacle).
• funnel-shaped.
  Widening from the base more or less gradually through the throat into an ascending, spreading, or recurved limb; often applied to a fused calyx or corolla. (see bell-shaped, rotate, salverform, urn-shaped)
• fused.
  United, as the petals together into a corolla tube or stamens onto petals; neither free nor adherent.
• fusiform.
  Elongate, widest at the middle, tapered to both ends.


• glabrous.
  Without hairs.
• gland (glandular).
  Small, often spheric body, on or embedded in the epidermis or at the tip of a hair, that exudes a generally sticky substance (e.g., Psorothamnus arborescens).
• glaucous.
  Covered with a generally whitish or bluish, waxy or powdery film that is sometimes easily rubbed off.
• glochid.
  In Cactaceae, reduced, barbed, deciduous, bristle-like spine (e.g., Opuntia).
• glume.
  In Poaceae, each of generally two sheathing bracts that are the lowermost parts of a spikelet, subtending one or more florets. (see floret, lemma, palea, spikelet)
• graduated.
  In Asteraceae, pertaining to an involucre in which the phyllaries are of unequal length, with the outer shortest, the inner longest, and a gradual transition through multiple series between.
• grain.
  In Poaceae, dry, indehiscent, 1-seeded fruit in which the fruit wall is fused to the seed; often appearing to be a naked seed.
• granular.
  Covered with minute bumps. (see papillate, tubercle)
• grassland.
  Vegetation characterized by various species of grasses, often mixed with various other kinds of herbs (not grasses) and sometimes scattered, low-growing shrubs.
• gymnosperm.
  Plant that bears woody or fleshy cones, not flowers, in which "naked seeds" (hence, gymno-sperm) are not enclosed in an ovary; woody (e.g., pine, sequoia, ephedra, yew).


• habit.
  Characteristic mode of growth, general form, or shape of a plant (e.g., cespitose, herb, scapose, shrub).
• habitat.
  Natural setting or conditions under which a plant lives (e.g., saltbush scrub, vernal pool, granitic soil among pines, montane forest).
• hair.
  Thread-like epidermal outgrowth. (see glabrous, canescent, ciliate, prickle, puberulent, scabrous, scale, strigose, tomentose)
• haploid.
  Having one set of chromosomes (maternal or paternal); n. (see diploid, n, polyploid)
• hastate.
  Arrowhead-shaped, with two basal lobes oriented more or less perpendicularly to the long axis. (see sagittate)
• head.
  1. In flowering plants excluding Asteraceae and some other groups, a dense, often spheric inflorescence of sessile or subsessile flowers. 2. In Asteraceae and some other groups, a head-like inflorescence is one in which sessile or subsessile inflorescence units (e.g., heads in Asteraceae, fl clusters enclosed by involucres in Eriogonum), instead of individual flowers, are attached in a short dense cluster without an evident axis or branches.
• hemispheric.
  Shaped like a dome or half sphere.
• herb.
  Plant that, at least above ground, is generally non-woody and of less than one year or growing season in duration. (see annual, biennial, perennial, subshrub)
• herbaceous.
  Lacking wood; having the characteristics of an herb.
• herbage.
  Above-ground, non-woody parts of a plant, including especially the leaves and young stems taken together, excluding flowers and fruits.
• heterostylous.
  Pertaining to a taxon in which individual plants produce only one of two or more flower types, each type differing in the lengths of styles relative to stamens; a rare condition in angiosperms. (see homostylous)
• homostylous.
  Pertaining to a taxon in which only one type of flower is produced, in which there is no significant variation in the lengths of styles relative to stamens; the usual condition in angiosperms. (see heterostylous)
• hypanthium (hypanthia).
  Structure generally in the shape of a tube, cup, or bowl, derived from the fused lower portions of the perianth and stamens, from which these parts seem to arise, and to which the ovary wall is fused in an inferior ovary (to which the ovary wall is partially fused in a half-inferior ovary; from which the ovary is free in a superior ovary).


• included.
  Not protruding out of surrounding structure(s) (e.g., stamens included in corolla). (see exserted)
• indehiscent.
  Not opening inherently to release contents; usually pertaining to fruits. (see dehiscent)
• indusium (indusia).
  In many ferns, a usually thin, often scale-like outgrowth of the leaf blade surface that covers a sorus and protects the young sporangia; also called a true indusium. (see false indusium)
• inferior ovary.
  Ovary that is fused to the fused lower portions of the perianth and stamens (i.e., to the hypanthium), to the extent that these structures appear to arise at or above its summit. (see superior ovary)
• inflorescence.
  Entire aggregation of flowers or flower clusters and associated structures (e.g., axes, bracts, bractlets, pedicels); often difficult to determine as to type and boundaries but generally excluding full-sized foliage leaves.
• infraspecific.
  Below the species level or within a species; pertaining to variation within a species, whether taxonomically significant (e.g., characterizing subspecies or varieties) or not (e.g., characterizing forms or minor variants).
• intergrade.
  To merge gradually from one extreme to another through a more or less continuous series of intermediates.
• intermediate.
  Between extremes or parental taxa in size, shape, color, flowering time, habitat preferences, geographic ranges, or other ways.
• internode.
  Segment of an axis (generally a stem) between successive positions (nodes) from which one or more structures (especially leaves, buds, branches, or flowers) arise.
• interrupted.
  Having parts spaced unevenly, clustered; pertaining especially to inflorescences in which the flowers are clustered. (see continuous)
• intertidal.
  Pertaining to marine habitats that are submerged at high tide and exposed at low tide.
• involucel.
  Secondary involucre (group of bracts) within an inflorescence (e.g., those subtending the secondary umbels in members of Apiaceae).
• involucre.
  Group of bracts more or less held together as a unit, subtending a flower, fruit (acorn cup), or inflorescence.


• keel.
  1. Ridge or crease more or less centrally located on the long axis of a structure, generally on the abaxial side. 2. Two lowermost, fused petals of many members of Fabaceae.
• lanceolate (lance- in combining forms).
  Narrowly elongate, widest in the basal half, often tapered to an acute tip.
• lateral.
  Pertaining to the side(s) of a structure (e.g., laterally compressed, meaning flattened side-to-side; lateral branch; lateral appendage). (see terminal)
• leaf.
  Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).
• leaflet.
  Leaf-like unit of a compound leaf; distinguished from a leaf by the absence in its axil of a bud, branch, thorn, or flower; either simple (leaf 1-compound, with 1° leaflets) or compound (leaf 2-compound, with 1° and 2° leaflets; 3-compound, with 1°, 2°, and 3° leaflets; etc.).
• legume.
  In Fabaceae (legume family), a dry or somewhat fleshy, 1- to many-seeded fruit from a simple pistil, typically dehiscent longitudinally along two sutures and splitting into halves that remain joined at the base, sometimes indehiscent or breaking crosswise into 1-seeded segments; a plant with such a fruit.
• lemma.
  In Poaceae, the lower, generally larger of two sheathing bracts subtending a flower, generally ensheathing the palea (in a sterile lemma, the associated flower and sometimes palea are rudimentary or absent); with the palea and flower, comprising the floret. (see floret, glume, palea, spikelet)
• lenticel.
  Each of many spongy or callused areas of various shapes, sizes, and colors, most commonly on surfaces of young stems (including twigs) or fruits.
• lenticular.
  Lens- or discus-shaped, with both major sides convex.
• ligulate flower.
  In Asteraceae, a bisexual, bilateral flower with the outer portion of the corolla (the ligule) strap- or fan-shaped, 5-lobed; appearing only with other ligulate flowers in a liguliflorous head. (see disk flower, ray flower)
• ligule.
  1. In Asteraceae, the 5-lobed, strap- or fan-shaped outer portion of the corolla of a ligulate flower. 2. In most Poaceae and some other grass-like plants, an appendage at the adaxial junction of leaf sheath and blade, generally membranous, sometimes formed of hairs. 3. In Isoetes and, more obscurely, in Selaginella, a membrane that wholly or partially covers a sporangium.
• liguliflorous head.
  In Asteraceae, a head composed entirely of ligulate flowers. (see disciform head, discoid head, radiant head, radiate head)
• limb.
  In calyces or corollas with fused sepals or petals, the expanded, often lobed portion distal to the tube or throat; in some free or nearly free sepals and petals, the expanded portion distal to the stalk-like base (claw).
• linear.
  Elongate, with nearly parallel sides; narrower than elliptic or oblong.
• lip.
  1. Upper or lower of two parts in a bilateral, unequally divided calyx or corolla. 2. In Orchidaceae, generally the largest, lowest, most highly modified perianth part.
• lobe.
  1. Major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. Free tips of otherwise fused structures, such as sepals or petals; larger than teeth.
• loculicidal.
  Pertaining to dehiscence of a fruit (capsule) by a longitudinal line through the wall at or near the center of each chamber, such that each resulting segment corresponds to the two adjacent halves of two adjacent chambers, usually with a placenta-bearing septum centrally. (see circumscissile, septicidal)
• longitudinal.
  Pertaining to length or the lengthwise dimension; parallel to the axis. (see transverse)


• margin.
  Edge, generally of a leaf or perianth part.
• marsh.
  Permanently or periodically inundated, mostly or completely treeless vegetation characterized by semi-aquatic herbs or subshrubs.
• meadow.
  Open grass- or sedge-characterized vegetation more or less surrounded by woodland or forest; meadow soils are generally seasonally moist and frequently are composed of fine-grained sediments.
• membranous.
  Thin, dry or moist, pliable, often more or less translucent or variously colored, sometimes green (e.g., Elymus cinereus ligule). (see scarious)
• mericarp.
  One of the generally dry, generally indehiscent, 1--few-seeded, 1-carpelled segments into which certain fruits separate at maturity (e.g., those of Apiaceae).
• meter.
  Basic unit of length in the metric system, equal to 39.4 inches, slightly more than a yard (abbreviation: m).
• millimeter.
  One-thousandth of a meter; one-tenth of a centimeter (abbreviation: mm).
• mixed-evergreen forest.
  Vegetation characterized by a variable mixture of mostly or only hardwood tree species, most of which retain their leaves throughout the year.
• monoecious.
  Pertaining to a taxon in which individuals produce both male and female reproductive structures and do not produce bisexual reproductive structures (e.g., Alnus rhombifolia). (see dioecious)
• montane.
  Pertaining to mountains; vegetational/altitudinal zone between the foothill and subalpine zones.
• mucro (mucronate).
  Abrupt, short, sharp, narrow, terminal point, tip, or projection (e.g., Isolepis fruit).


• n.
  Number of chromosomes in haploid cells. (see diploid, polyploid)
• native.
  Occurring naturally in an area, as neither a direct nor indirect consequence of human activity; indigenous; not alien. (see naturalized, waif)
• naturalized.
  Alien (not native) and reproducing either sexually (e.g., by spores, seeds) or vegetatively (e.g., by sprouts, suckers) in the absence of any benefit, intentional or not, direct or indirect, of human activity, and thereby persisting beyond initial generation or establishment. (see native, waif)
• nectar.
  Sugary solution, produced in nectaries, consumed primarily as an energy source by animal visitors, usually pollinators.
• nectary.
  Variously shaped, nectar-producing structure(s) usually at or near the base of the inside of a flower (or sometimes elsewhere, such as in a perianth spur or on a petiole) (e.g., Symphoricarpos rotundifolius).
• needle.
  Narrowly linear, often waxy, generally evergreen leaf, especially of conifers.
• nodding.
  Pertaining to a structure (e.g., flower, fruit) borne on a stalk that is curved downward (e.g., Aquilegia formosa flower).
• node.
  Position on a stem from which one or more structures (especially leaves, buds, branches, or flowers) arise. (see internode)
• nut.
  Mostly dry, sometimes fleshy or pulpy, usually indehiscent fruit in which a single seed is encased in a hard shell (e.g., Quercus palmeri). (see drupe)
• nutlet.
  Small, dry nut or nut-like fruit, usually several of which are produced by a single flower (e.g., Boraginaceae, Lamiaceae). (see nut, drupe)


• ob-.
  Prefix indicating inversion of shape (e.g., lanceolate and oblanceolate leaf blades are widest below and above the middle, respectively).
• oblique.
  Having unequal sides or an asymmetric base.
• oblong.
  Longer than wide, with nearly parallel sides; wider than linear. (see elliptic)
• obtuse.
  Having a short-tapered, blunt tip or base, the sides convex or straight and converging at more than a right angle. (see acute)
• ocrea, ochrea (ocreae, ochreae).
  In Polygonaceae, generally scarious sheath around the stem formed by the fusion of stipules.
• open.
  Uncongested or diffuse; especially pertaining to the disposition of flowers in an inflorescence. (see dense)
• opposite.
  1. Arranged in pairs along an axis (e.g., two leaves per node). (see alternate, whorled) 2. Occurring in the same rank, directly above or below, as "stamens opposite petals". 3. Located directly across from.
• ovary.
  Ovule-bearing, usually wider, basal portion of pistil, normally developing into a fruit as ovules become seeds; may be simple (one carpel, one chamber) or compound (two or more carpels, one or more chambers).
• ovary stalk (fruit stalk).
  Pedestal-like, apical prolongation of a floral receptacle (often termed elsewhere a carpophore) or basal constriction of an ovary (often termed elsewhere a gynophore), above the level of perianth insertion, each with the result that the ovary or fruit appears to be stalked over and above the pedicel (whereas the demarcation between pedicel and ovary- or fruit-stalk is observable as the point of perianth insertion, carpophores generally are distinguished from gynophores only by anatomical study).
• ovate.
  Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf. (see ovoid)
• ovoid.
  Egg-shaped (i.e., widest below the middle) in three dimensions, as a fruit. (see ovate)
• ovule.
  In gymnosperms and angiosperms, structure containing an egg, and normally developing into a seed after fertilization.


• palea (paleae, paleate).
  1. In Asteraceae, a scale-like bract that subtends an individual flower on the receptacle (equal to "chaff scale" in TJM,1993), absent in some genera, restricted to a ring separating ray and disk flowers in most tarweed species. 2. In Poaceae, the distal, generally smaller of two sheathing bracts subtending a flower, generally 2-veined and -keeled and ensheathed by the lemma; with the lemma and flower, comprising the floret. (see floret, glume, lemma, spikelet)
• palmate.
  More than two structures or parts (e.g., veins, lobes, or leaflets) radiating from a common point in two dimensions (i.e., in one plane). (see pinnate, ternate)
• panicle.
  1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, a branched inflorescence in which the basal or lateral flowers (or some of them) open before the terminal or central flowers on any axis. (see cyme) 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a panicle-like inflorescence is one in which at least some of the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are attached (stalked or unstalked) to branches and not directly to the main axis of the inflorescence and in which floral development may or may not proceed as in 1.
• papillate.
  Pertaining to a surface (e.g., of a leaf, stigma, fruit) bearing small, rounded or conic protuberances (papillae; singular papilla).
• pappus.
  In Asteraceae, the aggregate of structures such as awns, bristles, or scales arising from the top of the inferior ovary, in place of the calyx.
• parasite.
  Plant that benefits by taking resources from a physical connection to a host plant of another species; green parasites (hemiparasites) derive water and dissolved inorganic substances (e.g., mineral nutrients) from the connection and often are able to survive without it, while non-green parasites (holoparasites) obtain in addition energy-rich, organic compounds (products of photosynthesis) from the connection and cannot survive without it; the connection may or may not involve a fungal intermediate, and may or may not be detrimental to the host.
• parietal.
  Pertaining to placentas on the inside surface of the ovary wall in a compound ovary with one or more chambers.
• peat.
  Material formed by the partial decomposition in water of plant tissues, especially mosses (Sphagnum) or sedges.
• peatland.
  Moss- or herb-characterized freshwater wetland with nutrient-deficient substrate and accumulated peat; often said elsewhere to be bogs if acidic, fens if basic.
• pedicel.
  Stalk of an individual flower in an inflorescence, or the corresponding structure in fruit. (see peduncle, ray)
• peduncle.
  Stalk of an individual flower borne singly, not in an inflorescence, or of an entire inflorescence, or the corresponding structure in fruit; the stalk subtending an involucre (e.g., in Asteraceae, Polygonaceae). (see pedicel, ray)
• peltate.
  With the stalk attached toward the middle, not at a margin, of a flat structure such as an indusium, scale, or leaf.
• pendent.
  Drooping, hanging, or suspended from a point of attachment above (e.g., Amelanchier utahensis fruit).
• perennial.
  Completing life cycle (germination through death) in more than two years or growing seasons, generally non-woody (at least above ground) to woody; includes perennial herbs as well as subshrubs to trees; the abbreviation "per" only refers to perennial herb, not to the word "perennial" alone. (see annual, biennial)
• perianth.
  Calyx and corolla collectively, whether or not they are distinguishable.
• perianth part.
  Individual member of a perianth; used whether or not calyx and corolla are distinguishable, but usually when they are not.
• perigynium.
  Variously shaped, sac-like structure enclosing the ovary and achene in Carex and Kobresia.
• persistent.
  Not falling off; remaining attached. (see deciduous, ephemeral)
• petal.
  Individual member of the corolla, whether fused or not; if fused, often equal in number to the number of corolla lobes; often conspicuously colored. (see sepal)
• petiole.
  Leaf stalk, connecting leaf blade to stem; sometimes more or less indistinct.
• phyllary.
  In Asteraceae, a bract of the involucre.
• pinna (pinnae).
  In ferns, primary division of a compound or dissected leaf blade.
• pinnate.
  Feather-like; pertaining to veins, lobes, leaflets, or other structures arranged in two dimensions (i.e., in one plane) along either side of an axis; a leaf is odd-pinnate if there is a terminal leaflet, even-pinnate if there is not, and either odd- or even-pinnate may be 1-pinnate (blade divided into primary leaflets), 2-pinnate (primary leaflets divided into secondary leaflets), 3-pinnate (secondary leaflets divided into tertiary leaflets), etc. (see compound leaf, palmate, ternate, plumose)
• pinnule.
  In ferns, secondary division of a compound or dissected leaf blade, primary division of a pinna.
• pistil.
  Female reproductive structure of a flower, composed of an ovule-containing ovary at the base, one or more pollen-receiving stigmas at the tip, and generally one or more styles between ovary and stigma. A flower may have one or more simple pistils (each a single, free carpel with a single ovary chamber, placenta, and stigma) or one compound pistil (two or more fused or partially fused carpels, the exact number often equaling the number of ovary lobes, ovary chambers, placentas, styles, or stigmas).
• pistillate.
  Pertaining to flowers, inflorescences, or plants with fertile pistils but sterile or missing stamens (e.g., Salix laevigata pistillate flower). (see staminate)
• placenta.
  Structure or area to which ovules are attached in an ovary; variously shaped and positioned.
• planoconvex.
  Flat or nearly so on one side, rounded on the other (e.g., Carex harfordii perigynium).
• pleated.
  Having accordion-like folds.
• plumose.
  Plume-like, usually with the parts arrayed in three dimensions around an axis, or in tufts held together at the base; usually pertaining to small, finely divided structures, such as certain stigmas and pappus elements. (see pinnate)
• pollen (pollen grain).
  In gymnosperms and angiosperms, structure containing the sperm; when sperm fertilizes an egg, the egg and surrounding ovule normally develop into a seed.
• pollen sac.
  Each of the one, two, or four pollen-bearing portion(s) of an anther.
• pollination.
  Placement of pollen, by an insect, the wind, or other vector, on a stigmatic or ovular surface, through which pollen tube growth and fertilization may occur; self-pollination involves only one plant, cross-pollination occurs between plants.
• pollinium (pollinia).
  Especially in Asclepias and related genera, and in Orchidaceae, a mass of adherent pollen grains disseminated as a unit.
• polyploid.
  Having three or more sets of chromosomes; 3n, 4n, etc. (see diploid, haploid, n)
• pome.
  In Rosaceae, a fleshy, indehiscent fruit, such as an apple or pear; derived from a hypanthium (represented as outer fleshy material and skin) surrounding and ± fused to a compound ovary (represented as (1)2—5 papery-walled, radiating segments alternating with fleshy material, as in, e.g., Amelanchier utahensis fruit) or to (1)2—5 free ovaries, each with a ± stony outer layer. (see berry, drupe)
• prickle.
  Sharp-pointed, stiff or somewhat flexible projection, originating at or near the surface and neither subtending an axillary bud or branch nor subtended by a leaf or leaf scar, without leaves, leaf scars, buds, or branches (e.g., Rosa woodsii stem); loosely used for any sharp projection. (see armed, spine, thorn)
• prostrate.
  Lying flat on the ground. (see ascending, decumbent)
• protandrous.
  Pertaining to a bisexual flower in which pollen release precedes stigma receptivity, or to a plant with staminate and pistillate flowers in which this is true, with the result that cross-pollination is favored.
• protogynous.
  Pertaining to a bisexual flower in which stigma receptivity precedes pollen release, or to a plant with staminate and pistillate flowers in which this is true, with the result that cross-pollination is favored.
• proximal.
  Closer to the base, origin, or point of attachment, or farther away from the edge or tip. (see distal)
• puberulent.
  Minutely hairy.


• raceme.
  1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, an unbranched inflorescence in which the flowers are borne on pedicels and nearly always open from the bottom to the top of the inflorescence. (see panicle, spike) 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a raceme-like inflorescence is one in which the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are stalked and attached directly to the main axis of the inflorescence, not to branches, and in which floral development may or may not proceed as in 1.
• rachis.
  In ferns, primary axis of a compound or dissected leaf blade.
• radial.
  Divisible into mirror-image halves in three or more ways. (see asymmetric, bilateral, biradial)
• radiant head.
  In Asteraceae, a discoid head with a peripheral ring of flowers having much enlarged, often bilateral corollas.
• radiate head.
  In Asteraceae, a head composed of central disk flowers and marginal ray flowers. (see disciform head, discoid head, liguliflorous head, radiant head)
• rank.
  1. Row or column of parts along an axis (e.g., leaves on an erect stem arranged in four vertical rows are 4-ranked). (see alternate, opposite) 2. In classification, a taxonomic level (e.g., family, genus, species, subspecies, variety). (see taxon)
• rare.
  Extremely unlikely to be present in appropriate habitats, often restricted to a small number of sites. (see endangered, threatened, uncommon)
• ray.
  1. Each of a number of radiating axes, as a primary branch in a compound umbel. (see pedicel, peduncle) 2. In Asteraceae, the flat, strap- or fan-shaped, often 3-lobed outer portion of the corolla of a ray flower.
• ray flower.
  In Asteraceae, a generally pistillate or sterile, bilateral flower with a flat, strap- or fan-shaped, often 3-lobed outer portion of the corolla (ray); appearing in a ring around a central cluster of disk flowers. (see ligulate flower, disk flower)
• receptacle.
  1. In individual flowers, the structure to which flower parts are attached. 2. In heads or head-like inflorescences, especially in Asteraceae, the structure to which flowers or sometimes heads are attached.
• recurved.
  Gradually curved downward or backward.
• reduced.
  Smaller, less lobed, simpler, etc.
• redwood forest.
  Vegetation characterized by Sequoia sempervirens, occurring on slopes and canyons of coastal mountain ranges.
• reflexed.
  Abruptly bent or curved downward or backward.
• reniform.
  Kidney-shaped; often pertaining to a leaf in which the blade base on both sides of the petiole is rounded and concave. (see cordate)
• rhizome.
  1. In seed plants, stem that is often elongate, generally more or less horizontal and underground; distinguished from roots by bearing of leaves, leaf scars, axillary buds, etc. (see stolon) 2. In ferns, stem that is located underground, embedded in leaf litter, on rocks or in rock crevices, or on trees or tree branches, often scaly or hairy; distinguished from roots by bearing of leaves (roots rarely bear leaves) and their greater diameter.
• rib.
  1. Ridge, as on a fruit. 2. Raised vein, as on a leaf or other part (e.g., Carex hendersonii perigynium).
• riparian.
  Pertaining to communities that occupy the banks, channels, and flood plains of waterways.
• root.
  Generally underground axis or axes of a plant; distinguished from stems by not bearing leaves, leaf scars, axillary buds, flowers, etc.; generally growing into the ground from the base of a stem, its functions include anchorage, absorption of water and nutrients, and food storage. (see bulb, corm, rhizome, caudex, tuber, stolon)
• rosette.
  Radiating cluster of leaves generally at or near ground level.
• rotate.
  Wheel-shaped, spreading, or saucer-shaped; often applied to a fused corolla with a short or nonexistent tube and a spreading limb. (see bell-shaped, funnel-shaped, salverform, urn-shaped)
• ruderal.
  Plant, usually alien, occurring in waste areas, along roadsides, and in other places disturbed by humans; pertaining to such a plant.


• sagittate.
  Arrowhead-shaped, with two basal lobes oriented nearly parallel to the long axis. (see hastate)
• salverform.
  Having a slender tube and an abruptly spreading, flat limb; often applied to a fused corolla. (see bell-shaped, funnel-shaped, rotate, urn-shaped)
• savanna.
  Vegetation characterized by various species of grasses with scattered individual trees; with less canopy cover than a woodland (canopies do not touch).
• scabrous.
  Rough to the touch, generally owing to short stiff hairs (e.g., Brickellia pappus).
• scale.
  1. Wide, appressed, membranous, epidermal outgrowth (e.g., Cheilanthes covillei). (see hair) 2. Structure (bud scale) partially or entirely covering an over-wintering bud (e.g., Salix gooddingii bud). 3. In gymnosperms, a woody, seed-bearing structure (cone scale) attached to the cone axis (e.g., Abies magnifica). 4. In Asteraceae, flat, membranous pappus element (e.g., Hymenoxys hoopesii). Leaves or bracts may be scale-like in one or more of the preceding ways.
• scapose.
  Pertaining to a plant or an inflorescence in which a relatively long peduncle (scape) arises, sometimes with leaf- or scale-like bracts but without true foliage leaves, from a rosette or other arrangement of leaves at ground level.
• scar.
  Mark left by the natural separation of two structures, as a leaf scar on a stem.
• scarious.
  Thin, dry, pliable, translucent or variously colored but not green (e.g., Carex incurviformis pistillate flower bract). (see membranous)
• scree.
  Relatively unstable, sloping accumulation of small rock fragments, often at a cliff base. (see talus)
• scrub.
  Vegetation characterized by shrubs; may be classified by habitat type or by characteristic species; shrubland.
• sculpture.
  Surface ornamentation or topography, often visible only when magnified, as on a seed or pollen grain (e.g., Plagiobothrys nothofulvus nutlet).
• seed.
  Any fertilized ovule, but in descriptions pertaining to the fully mature condition (i.e., at full cone or fruit maturation), unless noted otherwise.
• segment.
  1. Ultimate or smallest division of a compound leaf (then the segment is also a leaflet) or dissected leaf — not a marginal lobe, tooth, bristle, etc. 2. Part into which an organ is naturally or apparently divisible, such as of a calyx, corolla, fruit, etc. 3. Specified length, such as of a stem, root, style, etc.
• sepal.
  Individual member of the calyx, whether fused or not; if fused, often equal in number to the number of calyx lobes; generally green. (see petal)
• septicidal.
  Pertaining to dehiscence of a fruit (capsule) by a longitudinal line through the wall at or near the center of each septum, such that each resulting segment corresponds to a single chamber, with placentas placed variously. (see circumscissile, loculicidal)
• septum (septa, septate).
  Wall between chambers in a hair, root, compound ovary, or other structure.
• series.
  Group of structures of one kind (e.g., involucral bracts, sepals, petals, stamens) of similar size or shape, usually more or less in a row or whorl.
• serpentine.
  Pertaining to rocks, or soils derived from them, with generally low levels of calcium and other nutrients, and high levels of magnesium, iron, and certain toxic metals; many plant taxa are restricted to or excluded from serpentine.
• serrate.
  Having margins with sharp, fine to coarse teeth generally pointing tipward, not outward; margins with such teeth on such primary teeth are doubly serrate. (see dentate)
• sessile.
  Without a petiole, peduncle, pedicel, or other kind of stalk.
• sheath.
  Surrounding or partially surrounding, often tubular structure or part of a structure, such as a leaf base in Apiaceae or Poaceae.
• shoot.
  Pertaining collectively to a young stem or twig and its appendages (e.g., new growth in the spring), or to all above-ground parts of a plant (i.e., shoot system). A short-shoot (i.e., spur) is a shoot on some woody plants that undergoes only limited elongation, so that the internodes between appendages (leaves, flowers, etc.) are very short.
• shrub.
  Woody plant of relatively short maximum height, with generally many branches from the base. (see tree, subshrub, perennial)
• simple.
  Composed of a single part; undivided; unbranched. (see compound)
• sinus.
  Usually pertaining to margins of leaves, sepals, petals, or other parts, an indentation between adjacent lobes or teeth.
• sorus (sori).
  In many ferns, a distinct cluster of sporangia.
• spheric.
  Globe- or ball-shaped; circular in three dimensions.
• spike.
  1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, an unbranched inflorescence in which the flowers are sessile and nearly always open from the bottom to the top of the inflorescence. (see panicle, raceme, head) 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a spike-like inflorescence is one in which the inflorescence units (e.g., heads in Asteraceae; spikelets in Poaceae and most Cyperaceae), instead of individual flowers, are sessile and attached directly to the main axis of the inflorescence, not to branches, and in which floral development may or may not proceed as in 1. (see spikelet)
• spikelet.
  1. In Poaceae, one or more florets (each a flower with subtending lemma and generally palea) and generally two subtending glumes; in a sterile spikelet, the flower(s) and sometimes palea(e) are rudimentary or absent. (see floret, glume, lemma, palea) 2. For definitions in Cyperaceae, see note after family description.
• spine.
  Sharp-pointed, usually stiff projection, derived from a leaf or leaf part (e.g., stipule, vein tip), and therefore often subtending an axillary bud or branch, without buds of its own (e.g., marginal spine of Cirsium arvense leaf); loosely used for any sharp projection. (see armed, prickle, thorn)
• sporangium (sporangia).
  In non-seed plants, a case or sac in which spores are produced, and from which they are released.
• spore.
  In non-seed plants, one of very many minute, haploid cells (in mass, often appearing dust-like) dispersed from sporangia on a diploid parent plant (sporophyte), normally developing into a small haploid plant (gametophyte) that produces eggs, sperm, or both, the fusion of which results in new diploid offspring.
• spreading.
  Oriented more or less perpendicularly to the axis of attachment; often, more or less horizontal.
• spur.
  1. Hollow projection or expansion, generally of a perianth part and containing nectar (e.g., Aquilegia formosa petals). 2. Shoot on some woody plants that undergoes only limited elongation, so that the internodes between appendages (leaves, flowers, etc.) are very short. (see shoot)
• stamen.
  Male reproductive structure of a flower, typically composed of a stalk-like filament and a terminal, pollen-producing anther. Filaments sometimes partly fuse to the corolla, or to other filaments to form a tube. (see anther, filament, pistil)
• staminate.
  Pertaining to flowers, inflorescences, or plants with fertile stamens but sterile or missing pistils (e.g., Salix laevigata staminate flower). (see pistillate)
• staminode.
  Sterile stamen, usually modified in appearance, sometimes petal-like or elaborate in structure (e.g., Penstemon palmeri).
• stellate.
  Pertaining to a hair or other structure with three or more branches radiating in two or three dimensions from a common point. (see forked)
• stem.
  Generally above-ground but sometimes below-ground axis or axes of a plant; distinguished from roots by bearing leaves, leaf scars, axillary buds, flowers, nodes, etc. (see bulb, caudex, corm, rhizome, root, stolon, tuber)
• sterile.
  Not reproductively functional; pertaining to a plant or plant part that does not produce or is not associated with the production of functional spores, pollen, ovules, or seeds (e.g., sterile leaf, sterile stamen, sterile flower, sterile floret). (see fertile)
• stigma.
  Part of a pistil on which pollen germinates, generally terminal and elevated above the ovary on a style, usually sticky or hairy, sometimes lobed.
• stipe.
  1. In ferns, a leaf stalk (analogous to a petiole of a leaf), connecting blade to rhizome. 2. In some Polygonaceae, a stalk-like base of a flower or of a hypanthium, distal to pedicel (stipe and pedicel separated by line of dehiscence or a bulge, or differences in thickness; if no such demarcation exists, the structure throughout is a pedicel, not in part a stipe).
• stipule.
  Appendage at base of a petiole, generally paired, variable in form but often leaf- or scale-like, sometimes a spine.
• stolon.
  Normally thin, elongate stem lying more or less flat on the ground and forming roots as well as erect stems or shoots (which become new, clonal plants) at generally widely spaced nodes; runner. (see rhizome)
• stomate (stoma, stomata).
  Minute pore on a leaf (less often, stem or other structure) through which gases pass into or out of a plant (generally, carbon dioxide in, oxygen and water vapor out); generally closed during times of water stress; sometimes used in identification.
• stone.
  In a drupe, the very hard inner ovary wall and the generally single seed it surrounds; occurring one or more per flower, free or variously fused (e.g., Prunus emarginata fruit).
• stout.
  Thick, sturdy, not slender.
• striate.
  With fine, longitudinal channels, lines, or ridges.
• strigose.
  With stiff, straight, sharp, appressed hairs.
• style.
  In many but not all pistils, the stalk-like part that connects ovary to stigma.
• sub-.
  Prefix meaning almost, just below, or somewhat imperfectly.
• subalpine.
  Pertaining to the vegetational/altitudinal zone just below timberline, between the montane and the alpine.
• submersed.
  Pertaining to a plant normally rooted and remaining underwater, or to a part of such a plant normally held underwater. (see aquatic, emergent)
• subshrub.
  Plant with the proximal above-ground stems woody, the distal stems and twigs not woody (or less so) and dying back seasonally. (see perennial, shrub)
• subtend.
  Occurring immediately below, as sepals subtending petals or leaves subtending axillary buds.
• subtidal.
  Pertaining to marine aquatic habitats that are continuously submerged, even at low tide.
• superior ovary.
  Ovary that is free from the perianth and stamens, or free from the fused lower portions of these structures (i.e., free from the hypanthium), to the extent that these structures appear to arise at its base, and it appears to arise from the top of the receptacle. (see hypanthium, inferior ovary)
• suture.
  Groove or line of dehiscence or fusion.
• swamp.
  Shrub- or tree-characterized vegetation that occurs in permanently wet soils with standing water.


• talus.
  Relatively stable, sloping accumulation of large rock fragments, often at a cliff base. (see scree)
• tapered.
  Gradually (not abruptly) narrower or smaller at base or tip. (see truncate)
• taproot.
  Primary root that grows more or less straight down into soil, is tapered to the end, and has smaller, lateral branches (e.g., carrot). (see fibrous)
• taxon (taxa).
  In classification, a group of organisms (such as plants) at any rank (e.g., species, genus, family); taxonomy is the science of classifying organisms. (see rank)
• tendril.
  Slender, generally coiling structure (generally stem, stipule, or leaf tip) by which a climbing plant becomes attached to its support (e.g., Lathyrus lanszwertii leaf).
• terminal.
  Pertaining to the tip of a structure (e.g., terminal bud). (see lateral)
• ternate.
  Lobed, dissected, or compound into three parts, once, as a clover leaf (e.g., Trifolium wormskioldii), or more than once; in a ternate-pinnate leaf, the leaf is divided into three leaflets, each of which is pinnately compound (e.g., Aralia californica); three structures or parts (e.g., veins, lobes, or leaflets) radiating from a common point. (see palmate, pinnate)
• thorn.
  Sharp-pointed, usually stiff projection, derived from a branch and therefore often subtended by a leaf or leaf scar, sometimes with leaf scars and buds of its own (e.g., Castela emoryi); loosely used for any sharp projection. (see armed, prickle, spine)
• throat.
  In calyces or corollas with fused sepals or petals, the expanded, fused portion distal to the tube and proximal to the limb.
• timberline.
  Region in high mountains where subalpine forests give way to treeless alpine vegetation.
• tomentose.
  Covered with densely interwoven, generally matted hairs.
• tooth (teeth).
  1. Small, pointed projection, such as on the margin of a leaf, sepal, or petal. 2. Free tips of otherwise fused structures, such as sepals or petals (somewhat archaic usage); smaller than lobes. (see dentate, serrate)
• transverse.
  Pertaining to width or the widthwise dimension; perpendicular to the axis. (see longitudinal)
• tree.
  Woody plant of medium to tall maximum height, with generally one trunk from the base (e.g., Sequoia sempervirens). (see shrub, perennial)
• truncate.
  Abruptly (not gradually) narrower or smaller at base or tip, as if cut straight across or nearly so. (see tapered)
• tube.
  In calyces or corollas with fused sepals or petals, the often more or less cylindric, fused portion at the base, proximal to the throat and limb.
• tuber.
  Short, thickened, fleshy, usually starchy, underground stem for storage (of water, food, or both) and sometimes propagation (e.g., potato). (see stem)
• tubercle.
  Small, wart-like projection (e.g., Cryptantha muricata nutlet).
• twig.
  In woody plants, a terminal stem segment, produced during the current or most recent growth period.
• twining.
  Climbing by the twisting or coiling of stems, tendrils, or other structures (e.g., Antirrhinum filipes).


• ultimate.
  Last, most distal, or smallest, as all the tips of a branching stem or the smallest divisions (segments) of a compound leaf or dissected leaf.
• umbel.
  1. In flowering plants excluding Asteraceae and some other groups, an inflorescence in which three to many pedicels and, if compound, branches (rays) radiate from a common point; characteristic of but not confined to Apiaceae. (see ray) 2. In Asteraceae and some other groups, an umbel-like inflorescence is one in which three to many stalked inflorescence units (e.g., heads in Asteraceae, umbels enclosed by involucres in Eriogonum), instead of individual flowers, radiate from a common point of attachment without an evident axis or branches.
• uncommon.
  Unlikely to be encountered; sometimes not present in appropriate habitats. (see abundant, common, rare)
• understory.
  Layer of vegetation growing beneath a canopy of taller plants.
• unisexual.
  Either male or female reproductive parts occurring and functional in the same plant or structure (e.g., flower, spikelet, inflorescence). (see bisexual, pistillate, staminate, dioecious, monoecious)
• urn-shaped.
  Widening more or less abruptly at the base and then gradually or abruptly narrowed toward the tip. (see bell-shaped, funnel-shaped, rotate, salverform)
• utricle.
  Mostly dry, dehiscent or indehiscent fruit from a generally compound pistil in which a balloon- or bladder-like ovary wall loosely encloses (or, in some Chenopodiaceae, is adherent to) a single seed.


• valve.
  1. In legumes or capsules opening by longitudinal lines, one of the parts into which the fruit is dehiscent (such fruits valvate). 2. In anthers, the flap of tissue resulting from dehiscence by a curved line (e.g., Lauraceae, some Berberidaceae). 3. In Ophioglossaceae, one of the parts into which the sporangium is dehiscent.
• vascular.
  Pertaining to plant veins or to plants with veins.
• vein.
  1. Tissue specialized for transport of substances within a plant: water and dissolved inorganic substances (e.g., mineral nutrients) through the xylem; energy-rich, organic compounds (products of photosynthesis) through the phloem. 2. Strand of such tissue, often seen as a line in surface view and as a bundle in transverse section.
• vernal.
  Pertaining to the spring season.
• vernal pool.
  Shallow, ephemeral body of water (i.e., one that becomes dry by spring or early summer) that occupies a depression, with underlying hardpan, claypan, or bedrock, in a grassland, foothill woodland, or chaparral.
• vestigial.
  Rudimentary; pertaining to a structure that is undeveloped, poorly developed, or degenerate and therefore non-functional.
• vine.
  Trailing, twining, or climbing plant, usually attached to its support by the twisting or coiling of stems, tendrils, or other structures (e.g., Phaseolus filiformis).


• waif.
  Alien, adventive; reproducing neither sexually (e.g., by spores, seeds) nor vegetatively (e.g., by sprouts, suckers) in the absence of any benefit, intentional or not, direct or indirect, of human activity, and therefore not persisting beyond initial generation or establishment, or reproducing to some extent but not persisting for more than a few generations or well beyond initial establishment and therefore not completely naturalized; generally not considered to be part of the flora, but of interest because of their potential to become naturalized, and thereby to have become so. (see alien, naturalized)
• wash.
  Normally dry drainage channel with only occasional surface flow (e.g., flash floods), in some cases with water movement and availability below in times of no surface flow.
• whorled (whorl).
  Arranged in groups of three or more at nodes or positions along an axis (e.g., three leaves per node). (see alternate, opposite)
• wing.
  1. Thin, flat extension or appendage of a surface or margin. 2. In many members of Fabaceae and in some other groups, each of the two lateral petals.
• wiry.
  Pertaining to roots, stems, hairs, and other structures that are slender, stiff, and tough.
• wood.
  Hardened, thickened, vascular tissue (xylem) under the bark of subshrubs, shrubs, trees, and some vines; number of concentric rings in wood often corresponds to years or growing seasons. (see bark)
• woodland.
  Vegetation characterized by small- to medium-sized trees, often with less continuous canopy cover than a forest and more than a savanna (canopies do not always touch).