raceme: a simple inflorescence ending in a non-floral bud and in which the flowers are stalked, i.e. an indeterminate inflorescence. Fig. 17 H. cf. raceme-like, spike.
raceme-like: applied to a simple inflorescence ending in a floral bud in which the flowers are stalked, i.e. resembling a raceme but determinate; also used for conflorescences of similar form, particularly where there has been reduction from more complex types. cf. raceme, spike-like.
rachilla: the axis of a grass spikelet above the glumes, also the axis in sedge spikelets.
rachis: the axis of an inflorescence, pinnate leaf, or of a pinna in a bipinnate leaf.
radical (basal): of leaves, clustered at the base of the stem. Fig. 2 I. cf. cauline, rosette.
radicle: the portion of an embryo that gives rise to the primary root system of a plant.
rainforest (closed forest): a forest dominated by broad-leaved trees with dense crowns that form a continuous layer (canopy) and with one or more of the following growth forms
ramiflory: the production of flowers and fruits behind the current foliage on woody branches formed in previous, but recent, seasons. adj. ramiflorous. cf. cauliflory.
rank: (1) a vertical row; (2) leaves that are 2-ranked are in 2 vertical rows, and may be alternate or opposite.
raphe: the part of the stalk of an anatropous ovule that is fused along the side of the ovule.
raphides: needle-like crystals that occur in bundles in the vacuoles of some plant cells.
ray floret (ray flower): a zygomorphic flower in many species of the family Asteraceae, usually formed towards the periphery of the head and with the corolla extended into a strap-shaped ligule. cf. disc floret.
receptacle: the often more or less expanded top of the stalk on which a flower or flower-head arises, Fig. 12 A; an axis on which sporangia arise in ferns.
recurved: curved backwards (and hence usually downwards), e.g. of the margins of a leaf. Fig. 10 D. cf. revolute, incurved, reflexed.
reflexed: bent sharply backwards (and hence usually downwards). cf. deflexed, inflexed.
regular: see actinomorphic.
reniform: kidney-shaped. Fig. 5 G.
replum: a longitudinal partition in fruits of the family Brassicaceae, see silicula, siliqua.
resinous: with a hardened sticky surface.
resupinate: twisted through 180° as in the ovary of most orchid (family Orchidaceae) flowers.
reticulate: forming a network or reticulum; e.g. of veins, Fig. 9 H.
retinaculum: (1) a hook-like structure to which another structure is tethered, as in Orchidaceae and Asclepiadaceae (the structure to which pollen masses are attached) or in Acanthaceae (the persistent stalk of an ovule); (2) the marginal outgrowth from a spadix, as in Zosteraceae. pl. retinacula.
retrorse: directed backwards (and thus often downwards).
retuse: having the apex rounded and with a small notch. Fig. 6 H.
revolute: rolled backwards (and thus often downwards), e.g. of the margins of a leaf. Fig. 10 E. cf. recurved, involute.
rhizoid: a thread-like, unicellular absorbing structure, in fern gametophytes and some non-vascular plants.
rhizome: an underground stem, usually growing horizontally. adj. rhizomatous. Fig. 1 N.
rhombic: having the form of a 2-dimensional diamond-shaped figure. Fig. 5 H.
rhomboid: having the form of a 3-dimensional diamond-shaped solid.
riparian: of plants growing by rivers or streams.
root: part of the underground axial system of a plant which does not bear leaves and tends to grow downwards or laterally in the soil. See also adventitious, aerial root.
rootstock: a swollen region at the junction of root system and stem, mostly below ground level.
rosette: a radiating cluster of leaves, usually close to the ground at the base of a plant. Fig. 2 I. See also radical.
rostellum: in orchids, a projection of the upper edge of the stigma in front of the anthers.
rosulate: clustered into a rosette.
rotate: term applied to a shortly tubular corolla with spreading lobes or limbs.
rudimentary: imperfectly developed and non-functional.
rugose (wrinkled): covered with coarse lines or furrows. Fig. 16 G.
rugulose: with tiny wrinkles.
ruminate: (1) of a surface or tissue, with an irregular, involuted outline, as in a rumen; (2) mottled in appearance.
runcinate: term describing a pinnatifid or pinnatisect leaf with sharply incised lobes or teeth pointing towards the base. Fig. 5 Q.
runner: a slender prostrate stem having a bud at the end which sends out leaves and roots.
rush: a plant belonging to the family Juncaceae or, more loosely, to various monocotyledons.
sac: a pouch. adj. saccate.
s.lat.: (sensu lato; Latin) of a plant name, in the broad sense.
s.str.: (sensu stricto; Latin) of a plant name, in the narrow sense.
sagittate: shaped like an arrow-head, with the two lobes at the base acute and retrorse; e.g of a lamina or sometimes applied to the base of a lamina. Fig. 7 H.
samara: a dry indehiscent fruit with its wall expanded into a wing. Fig. 18 U.
samphire: (in Australia) any plant of the tribe Salicorniae (family Chenopodiaceae), e.g. Sarcocornia, Halosarcia, Sclerostegia, or, a community dominated by one or more of these species.
saprophyte: an organism deriving its nourishment from dead organic matter and usually lacking chlorophyll. cf. parasite.
scabrous: rough to the touch; having the surface rough with minute hard processes or very short rigid hairs. Fig. 14 K.
scalariform: having a ladder-like pattern
scaberulous (scabridulous): slightly or minutely rough to the touch (diminutive of scabrous).
scale: (1) any thin and often scarious body, often a reduced or rudimentary leaf, e.g. covering a dormant bud, Fig. 3 G; (2) a thin flap of tissue, e.g. at the base of stamens; (3) a small papery surface structure on stems and leaves. Fig. 15 H & I.
scandent: climbing, usually applied in cases where special climbing organs are not developed.
scape: the stem-like flowering stalk of a plant with radical leaves.
scarious: dry and more or less membranous.
schizocarp: a dry fruit which splits into individual carpels, each of which is called a mericarp or coccus. Fig. 18 H.
schizocarpic capsule: a schizocarp in which the individual cocci or mericarps dehisce, as in some Rutaceae. Fig. 18 P.
sclerid: a cell with a lignified, thick and pitted wall.
sclerenchyma: mechanical tissue with heavily thickened cell walls.
scleromorph: a plant whose leaves (or stems, if leafless) are hard in texture, usually having thick cuticle and containing many fibres. cf. xeromorph.
scleromorphic: hard and with a large amount of fibrous tissue. cf. mesomorphic.
sclerophyll: a plant with hard, stiff leaves. adj. sclerophyllous.
scribbles: irregular lines on the barks of some eucalypts, being the old tunnels burrowed by moth larvae between the bark layers and exposed when the outer layer sheds.
scrobiculate: with shallow depressions.
scrub: dense vegetation dominated by shrubs.
scurfy: covered with small bran-like membranous scales.
section: a taxonomic grouping, in rank between genus and species.
secund: flowers or other structures arranged on, or turned to one side of an axis, e.g. inflorescence of many Grevillea species.
sedge: a plant belonging to the family Cyperaceae.
seed: the reproductive body formed from a fertilized ovule, and comprising an embryo, with or without endosperm or perisperm, and a surrounding protective seed coat or testa.
segment: a free or almost free part or subdivision of an organ. calyx and corolla segments of flowers called sepals and petals respectively; undifferentiated segments in flowers are called tepals.
segregate: distinct, kept apart: applied to taxa of various rank, e.g. segregate families of family Rosaceae s.lat. are Amygdalaceae, Malaceae and Rosaceae s.str.
semi: a prefix: half.
sens. lat.: see s.lat.
sensu: (Latin) in the sense of.
sepal: one of the outer leaf-like structures surrounding the corolla (if present) and fertile organs of the flower, usually green; collectively the calyx.
sepaline: of the sepals, e.g. sepaline calyptra, the calyptra formed from sepals.
sepaloid: resembling a sepal, i.e. not petaloid.
septal: (of nectaries) at the junction of the septa in the ovary.
septate: divided by internal transverse partitions.
septate-nodulose: used of leaves with prominent transverse septa.
septicidal capsule: dehiscing by splits along the sutures between adjacent carpels. Fig. 18 M.
septum: a partition or cross-wall; pl. septa.
seriate: in series, usually in whorls or apparent whorls; usually applied to floral parts.
sericeous (silky): covered with fine soft more or less straight appressed hairs aligned in the same direction, with a lustrous sheen and satin-like to the touch. Fig. 14 C.
serrate: saw-toothed, finely and regularly toothed.
serrulate: finely saw-toothed.
sessile: without a stalk, e.g. of a leaf without a petiole. Fig. 4 D.
seta: a bristle or stiff hair. adj. setaceous.
sheath: a tubular or rolled part of an organ, e.g. the lower part of the leaf in most grasses.
sheathing: clasping or surrounding the stem. Fig. 4 G.
shrub: a much-branched woody plant less than 8 m high and usually with many stems. Tall shrubs are mostly 2–8 m high; small shrubs 1–2 m high; subshrubs less than 1 m high.
sigmoid (sigmoidal): curved in two directions, an S-shaped curve.
siliceous: containing particles of silica.
silicula: a fruit like a siliqua but less than 3 times as long as broad.
siliqua: a dry dehiscent fruit derived from a superior ovary of two carpels and with 2 parietal placentas connected by a false septum, usually at least 3 times as long as broad, as in family Brassicaceae. Fig. 18 K.
silky: covered with fine soft more or less straight appressed hairs aligned in the same direction, with a lustrous sheen and satin-like to the touch. Fig. 14 C.
similifacial (isobilateral, isolateral): having structurally similar upper and lower surfaces. cf. dorsiventral.
simple: of a single piece or series; (1) of a leaf, with lamina not divided into leaflets (Fig. 3 H) cf. unifoliolate, compound; (2) of an inflorescence, unbranched with the pedicels arising from the main axis.
sinuate: with a deeply wavy margin. Fig. 8 K. cf. undulate.
sinus: the gap or recess between two lobes or segments.
smooth: of surfaces, without roughness or indumentum.
smut: fungal disease in which black sooty masses of spores cover the affected parts.
solifluction: slow, downward, movement of rock debris or soil saturated with melt-water over frozen subsoil.
solitary: borne singly, not grouped together, e.g. of flowers not grouped into an inflorescence. Fig. 17 L & M.
sorus: a discrete aggregate of sporangia in ferns.
spadix: a spicate inflorescence with a thickened, often succulent axis, the whole often being surrounded by a spathe. Fig. 17 Q.
spathaceous: like a spathe; with a spathe.
spathe: a large bract at the base of a spadix, which it encloses (at least initially) as a sheath.
spatheate: with spathes.
spathella: a closed membranous sac which envelopes the immature flower in some family Podostemaceae, rupturing irregularly as the pedicel elongates at anthesis.
spatheole: the ultimate spathe where an inflorescence or portions of an inflorescence are subtended by several spathes.
spathulate: spoon-shaped, e.g. of a leaf. Fig. 5 O.
species: a taxon comprising individuals, or populations of individuals, that show certain common features and are capable of interbreeding to produce fertile offspring. cf. genus.
spicate: in the form of a spike.
spicule: a small slender sharp-pointed process.
spike: a simple inflorescence, terminating in a non-floral bud, in which the flowers are sessile, i.e. a type of indeterminate inflorescence. Fig. 17 I. cf. spike-like, raceme.
spikelet: the small partial inflorescence (unit) in Poaceae, Cyperaceae and Restionaceae, composed of an axis bearing glumes, most of which enclose a small flower. Fig. 17 N.
spike-like: of a simple inflorescence, terminating in a floral bud and having the flowers sessile, i.e. a type of determinate inflorescence. cf. spike, raceme-like.
spine (thorn): a stiff process with a sharp point, formed by a modification of a plant organ that contains vascular tissue, e.g. a lateral branch or a stipule. Fig. 14 P. adj. spinose. cf. prickle.
spinescent: ending in a spine; modified to form a spine.
spinose: bearing spines.
spinule: a small spine.
spinulose: with spinules.
spiral: of leaves or floral organs, borne singly at different levels on the axis, but not in a single vertical line; leaves borne spirally are said to be alternate on the stem. Fig. 2 A. cf. whorled, alternate.
spirodistichous: 2-ranked and arranged spirally up stem.
spongy: having the texture of a sponge, the cells being separated by air spaces and containing air, as in pith or some seed coats.
sporangiate: bearing spores.
sporangiophore: the stalk of a sporangium.
sporangium: a structure in which spores are formed. pl. sporangia.
spore: a unicellular or few-celled asexual or sexual reproductive unit, not containing an embryo. cf. heterosporous, homosporous.
sporocarp: the fruiting body containing sporangia found in water ferns.
sporogenous: of cells or tissues, in which spores are formed.
sporophyll: a specialized leaf-like organ on which one or more sporangia are borne.
sporophyte: a plant, or phase of a life cycle, that bears the spores formed during the sexual reproductive cycle. cf. gametophyte.
spreading: extending horizontally, e.g. branches; standing out at right angles to axis, e.g. leaves or haris.
spur: A slender sac-like or hollow protuberance from a part of the calyx or corolla, often secreting nectar. adj. spurred.
squamule: a small scale, often within the sheathing base of a leaf.
squamulose: covered with small scales.
squarrose: usually sharply curved downward or outward in the apical region, e.g. of involucral bracts.
stamen: one of the male organs of the flower, consisting of a pollen-bearing anther and a filament or stalk. adj. staminate. cf. androecium.
staminal: of the stamens, e.g. staminal ring, ring or scar remaining after whorl of stames have fallen.
staminode: a sterile stamen, often reduced or modified.
staminophore: a band of tissue around the apex of the hypanthium in a eucalypt flower on which the stamens are inserted.
standard: the large upper petal of a pea flower, see Fabaceae subfamily Faboideae.
stellate: star-shaped; e.g. of hairs with radiating branches. Fig. 15 G.
stem: the main axis or a branch of the main axial system of a plant, developed from the plumule of the embryo and typically bearing leaves and generally above the ground.
sterile (barren): (1) without reproductive structures, not producing seed, spores or pollen; (2) of seeds, spores or pollen, not capable of germination. cf. fertile.
stereome: the tissue of a plant that provides mechanical support
stigma: the part of the carpel receptive to pollen, generally terminal on the style. adj. stigmatic.
stilt roots: oblique adventitious roots from the stem, as in some mangroves and palms.
stinging hair: a hollow hair seated on a gland which secretes an irritating fluid, e.g. as in Dendrocnide species.
stipe: (1) a stalk or support, e.g. of a gynoecium or carpel; (2) the petiole of a fern frond. adj. stipitate.
stipel (stipella): a stipule-like organ at the base of a leaflet. pl. stipels, stipellae.
stipitate: stalked; borne on a stipe; of an ovary, borne on a gynophore.
stipule: one or a pair of appendages sometimes developed at the base of a leaf in many dicotyledons; can be leaf-like, scarious or spinose. Fig. 4 I–L.
stolon: a more or less horizontal stem growing above ground and rooting at the nodes. adj. stoloniferous. Fig. 1 M.
stomate (stoma): a pore bounded by two guard cells in the epidermis, especially in leaves, for the exchange of gases between the plant tissues and the surrounding atmosphere. pl. stomates, stomata.
stomium: a region of dehiscence, e.g. of an anther in flowering plants, of a sporangium in ferns.
stone cell: short sclereid cell reponsible for the distinctive texture of some tissues, e.g. in the pear fruit.
striate: striped with parallel longitudinal ridges or lines. Fig. 16 H.
strigose: covered with sharp appressed rigid bristly hairs that are often swollen at the base. Fig. 14 M.
strobilus (cone): fertile stem with short internodes and sporophylls bearing sporangia, for example, as in many species of Lycopodium.
striolate: finely striate.
strophiole: see caruncle.
struma: a cushion-like swelling, e.g. at the apex of staminal filaments in Dianella.
style: the part of the carpel between the stigma and ovary, often elongated.
stylopodium: a disc-like enlargement of the base of the style.
sub-: a prefix: (1) nearly or almost, as in subequal: (2) below, under.
subsericeous: covered with appressed hairs aligned in the same direction, but lacking a lustrous sheen; like silky but coarser.
subshrub: undershrub; a small and sometimes sparsely branched woody plant less than 1 m high.
subspecies: a taxonomic category below species, differing in minor morphological characters such as size or shape of parts, and either partially or completely isolated, usually by means of geographical or ecological barriers.
subtend: to stand below or close to something, to enclose.
subtending: term describing a leaf or bract whose axil gives rise to a bud (the axillary bud) which may develop into a branch or inflorescence; less commonly (as in Notelaea species) more than one bud is subtended in each axil.
subulate: narrow and gradually tapering to a fine apex. Fig. 6 A.
sucker: a vegetative shoot of underground origin. Fig. 1 F.
sulcate: grooved; furrowed.
superficial: on the surface.
superfluous: unnescessary or needless.
superior: inserted above another organ or part; a superior ovary is free from the receptacle, with the perianth and stamens inserted below it or on a perigynous hypanthium. Fig. 12 A & D.
superposed: placed vertically over some other part.
suture: a seam or line as formed at the junction of two margins.
sward: extensive, more or less even cover of a surface, e.g. a lawn grass; cf. tussock.
syconium: a ‘fig’, the multiple fruit formed in figs (Ficus species) by the invagination of the floral axis where the minute flowers and fruits are actually inside the swollen inflorescence stem. Fig. 18 Y. cf. aggregate fruit, syncarp.
symmetric: divisible into two or more equal parts.
sympatric: of two or more taxa, with more or less similar or overlapping ranges of distribution. cf. allopatric.
sympetalous: see gamopetalous.
sympodial: with a growing point which either terminates in an inflorescence or dies each year, the growth being continued by a new lateral branch. cf. monopodial.
sympodium: a stem made up of a series of sympodial branches, so as to imitate a simple axis, as in some species of Dendrobium.
syn- (sym-): prefix: with, together.
synandrium: an androecium with the stamens cohering, as in some members of the family Araceae. cf. syngenesious.
synangium: composite sporangium with a number of loculi. pl. synangia.
syncarp: a multiple fruit consisting of several united fruits, originating from several originally free carpels, usually fleshy. Fig. 18 Z. cf. aggregate fruit, syconium.
syncarpous: a gynoecium consisting of a number of carpels in which at least the ovaries are united; the ovary is then said to be compound. Fig. 12 & Fig. 13 B–F. cf. apocarpous.
syngenesious: of the stamens of one flower fused together by the anthers to form a cylinder around the style, as in Asteraceae. cf. synandrium.
synonym: 1 of 2 or more names for the same taxon.
syntype: one of two or more specimens cited by the author at the time of publication of a name for which no holotype was designated.
systematics: the branch of bilogical science that deals with the giving of names (nomenclature) and classification, the establishing and defining of relationships (taxonomy); often used interchangeably with the term taxonomy.
taproot: the main, descending root of a plant that has a single, dominant root system.
taxon: a term used to describe a member of any taxonomic category, e.g. genus, species. pl. taxa.
taxonomy: the study of the principles and practices of classification, the establishing and defining of relationships; often used interchangeably with systematics, but strictly taxonomy is only part of systematics.
tendril: a long slender, coiled organ derived from an axis or leaf, or from part of one of these.
tepal: a free segment of a perianth that is not differentiated into a calyx and corolla.
terete: cylindric and elongated. Fig. 10 H.
terminal: at the apex.
terminal petiolule: the stalk of the terminal leaflet of a pinnately 3-foliolate leaf or an imparipinnate leaf; the stalk is usually jointed at the point where the rachis extension beyond the last leaflet meets the true petiolule of the leaflet. Fig. 3 C & K.
ternate: in threes, e.g. of a single leaf, having the leaflets arranged in groups of three. Fig. 3 K & L. cf. biternate.
terrestrial: of the land as opposed to living in water. cf. aquatic.
tessellated: with colours or shapes arranged in squares to give a chequered appearance, e.g. of bark.
testa: the seed coat.
tetrad: a group of four; as in four pollen grains remaining together at maturity in Ericaceae subfamily Styphelioideae.
tetradynamous: of an androecium, consisting of four stames of the same length and two of a different length; as in many Brassicaceae.
tetramerous: of a flower, having four segments in each perianth whorl, and usually in each whorl of stamens also.
tetrasporangiate (4-sporangiate): of an anther in which there are 4 pollen sacs (sites of pollen grain formation or microsporangia). cf. unisporangiate.
thallus: the vegetative body of a plant that is not differentiated into organs such as stems and leaves, e.g. algae, the gametophytes of many liverworts, and family Lemnaceae.
thorn (spine): a stiff process with a sharp point, formed by a modification of a plant organ that contains vascular tissue, e.g. a lateral branch or a stipule. cf. prickle.
throat: of a corolla tube or hypanthium, the top where the tube joins the lobes.
thyrse: a compound inflorescence ending in a vegetative (non-floral) bud and with mixed types of branching, the main axis bearing several or many lateral cymes. Fig. 17 C.
thyrsoid: a compound inflorescence which ends in a flower and in which the main axis is raceme-like and the lateral ones cymose, i.e. similar to a thyrse except for the terminal flower. Fig. 17 B.
tiller: the shoot of a grass, usually lateral and basal and more or less erect.
tomentellous: minutely tomentose.
tomentose: covered with dense intertwined hairs. Fig. 14 E. n. tomentum. cf. woolly.
tomentum: a dense covering of intertwined hairs. Fig. 14 E. adj. tomentose.
toothed: of margins, regularly or irregularly incised. Fig. 8 C.
torus: see receptacle.
tree: a woody plant usually with a single distinct trunk and generally more than 5 m high.
tri-: a prefix: in threes, as in: trifoliolate, having three leaflets; trimerous, with flower parts arranged in threes.
triad: a three-flowered inflorescence of dichasial form. Fig. 17 F.
triangular: a 2-dimensional shape, 3-angled and 3-sided. Fig. 5 K.
tribe: a taxonomic grouping, in rank between family and genus.
trichome: a hair, bristle, scale or other such outgrowth of the epidermis. Fig. 14 & Fig. 15.
trichotomous: branching almost equally into three parts.
trifid: deeply divided into three parts.
trifoliate: having three leaves. cf. trifoliolate.
trifoliolate: of a leaf, having three leaflets. Fig. 3 K & L. See also palmately trifoliolate, pinnately trifoliolate.
trigonous: triangular in cross-section and with the angles somewhat rounded. Fig. 10 F. cf. triquetrous.
trimerous: of a flower, having three segments in each perianth whorl and usually in each whorl of stamens also.
trimorphic: occurring in three different forms. cf. dimorphic.
tripinnate (3-pinnate): of a compound leaf, with lamina pinnately divided three times, i.e. the pinnules are again pinnately divided. Fig. 3 A. cf. bipinnate.
triplicate: folded three times.
triquetrous: triangular in cross-section and sharply angled; with three distinct longitudinal ridges. Fig. 10 G. cf. trigonous.
tristylous: heterostylous species with styles of 3 different lengths (short, mid, long).
trullate: ovate, but angled; like a brick-layer’s trowel; inverse kiteshaped.
truncate: with an abruptly transverse edge as if cut off, e.g. of a lamina apex (Fig. 6 F), or base (Fig. 7 D).
tuber: an underground storage organ formed by the swelling of a stem, e.g. a potato. adj. tuberous.
tubercle: a small wart-like outgrowth, e.g. forming the base of a hair.
tuberculate (warty): having the surface rough with tubercles or small wart-like outgrowths. Fig. 16 C.
tuberoid: a storage organ which is a tuber-like thickening of a root (and generally bears no lateral eyes) as in many terrestrial orchids.
tuberous: swollen; of roots tuber-like.
tumid: swollen; inflated.
tunicate: with coats or tunics; as in bulbs or corms covered with a thin membranous or fibrous outer layers.
turgid: swollen owing to high water content.
turion: a specialized dwarf shoot with modified leaves, and formed by some species in winter. Turions mostly fall from the parent plant, remain dormant over winter, and then sprout to form new individuals.
tussock: a large clump or tuft, usually of a perennial herb, especially grasses.
two-ranked (2-ranked): arranged in two rows on opposite sides of a stem and in the same plane. Fig. 2 B.
type: the designated representative of a taxon constituting a fixed point for the application of its name, for determining priority of usage.
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