ob-: a prefix: the other way around, as in obovate.
obconical: cone-shaped but attached to the narrower end.
obcordate: heart-shaped but attached at the pointed end, e.g. of a leaf lamina
oblanceolate: a 2-dimensional shape, lanceolate but broadest in the upper third. Fig. 5 L. cf. lanceolate.
oblate: almost circular, but with breadth slightly greater than the length. Fig. 5 F.
obligate: of parasites, unable to survive without the host. cf. facultative.
oblique (asymmetric): of a leaf, leaf base or other organ, having the sides unequal. Fig. 7 E.
obloid: a 3-dimensional shape, almost globose but with breadth slightly greater than the length.
oblong: a 2-dimensional shape, rectangular with length greater than breadth. Fig. 5 C.
obovate: a 2-dimensional shape, ovate but broadest above the middle. Fig. 5 M.
obpyriform: pear-shaped but broadest above the middle.
obsolescent: non-functional but not reduced to a rudiment.
obsolete: reduced to a rudiment, or completely lacking.
obtuse: blunt or broadly rounded, the converging edges separated by an angle greater than 900, e.g. of an lamina apex (Fig. 6 E) or of a lamina base (Fig. 7 C).
occluded: closed, in the sense of fused as in the leaves of Dianella species.
ocrea (ochrea): a sheath formed from two fused stipules encircling the node in Polygonaceae. Fig. 4 H. pl. ocreae.
oil glands (oil dots): small structures embedded in a leaf or other organ, secreting a volatile oil, mostly visible as small translucent dots (hand lens needed) against a strong light; usually making the organ aromatic when crushed.
one-foliolate (1-foliolate, unifoliolate): a compound leaf reduced to a single leaflet, usually recognized by the articulated or jointed ‘petiole’, which is in fact a petiole plus a petiolule. Fig. 3 I.
ontogeny: the development of a single organism, i.e. the sequence of stages through which it passes during its lifetime.
open forest: a forest dominated by trees with relatively narrow isobilateral leaves forming sparsely foliaged crowns (usually species of eucalypts); the forest canopy is sparse and often not continuous, allowing sunlight to reach the ground within the forest. cf. closed forest.
operculum (calyptra): a cap-like covering or lid of some flowers or fruits that becomes detached at maturity by abscission; e.g. (1) the cap on the buds of eucalypts, (2) the lid of circumsciss capsules.
opposite: inserted at the same level, as in leaves on the opposite side of the stem (Fig. 2 C & D), or in flowers the floral parts on the same radius. cf. alternate.
order: a taxonomic group consisting of one or more closely related families.
orbicular: orb-shaped, strictly a 3-dimensional shape but often used for a 2 dimensional circular shape, as for leaves (orbiculate).
orifice: a small opening or aperture.
orthotropous: of an ovule, with the body straight and erect so that the micropyle is terminal and the funicle attached at the base; embryo sac straight Fig. 21 A & B. cf. amphitropous, anatropous, campylotropous, hemitropous.
ortho-: a prefix: straight.
orthostichous: arranged in regular vertical rows on a stem or axis. cf. distichous.
orthotropic: mode of growth of vertical branches or leading shoots, especially in conifers where lateral (plagiotropic) branches may have different morphology.
osmophore: a scent-producing gland.
ostiole: an opening or pore, e.g. at the apex of a fig (fruit of Ficus species). adj. ostiolate
ovary: the basal portion of a carpel or a group of fused carpels in which one or more ovules are enclosed, and which after fertilization develops into the fruit.
ovate: a 2-dimensional shape, with the length 1–3 times the breadth, and broadest below the middle. Fig. 5 J.
ovoid: the 3-dimensional equivalent of ovate; egg-shaped.
ovule: a structure in seed plants within which one or more megaspores are formed, and which after fertilization develops into the seed.
ovuliferous: bearing ovules (e.g. applied to scales in a megasporangiate cone in gymnosperms).
ovulode: a sterile ovule.
p.p.: (pro parte, Latin) in part; in nomenclature, to denote that the preceding taxon includes more than 1 currently recognized entity, and only 1 of those entities is being considered.
pachymorph: applied to the rhizome systems of some bamboos where growth is determinate and sympodial, the plants forming large clumps with short rhizomes, the culms arising terminally from the rhizomes and new rhizomes arising laterally.
packing bracts: bracts that fill out the spaces between flowers and form the surface of the spike, as in Xanthorrhoea species.
palea: (1) the upper of 2 bracts enclosing the flower of a grass; (2) one of the chaffy scales on the petiole and rachis of many ferns.
palmate (digitate): (1) of a compound leaf with 3 or more leaflets arising from the one point at the top of the petiole, Fig. 3 E & L; (2) of veins in a lamina, radiating from the one point, Fig. 9 C & D. adv. palmately.
palmately trifoliolate: of a leaf, with 3 leaflets arranged palmately, i.e. all the petiolules of about the same length. Fig. 3 L. cf. pinnately trifoliolate.
palmatifid: of a leaf cut into lobes to less than halfway in a palmate form. Fig. 5 U.
palmatisect: of a leaf cut into lobes to more than halfway in a palmate form. Fig. 5 V.
palmativeined: of leaves, palmately veined, i.e. with the (main) veins radiating from one basal point.
palynology: the scientific study of pollen.
panicle: a compound inflorescence with a main axis and lateral branches which are further branched, and in which each axis ends in a flower or flower bud. Fig. 17 A. adj. paniculate.
papilionaceous: (papilionate) butterfly-like; with a corolla like that of a pea, as in the family Fabaceae subfamily Faboideae.
papilla: a small elongated or nipple-shaped protuberance on an organ. pl. papillae.
papillose: of a surface, rough with papillae. Fig. 16 D.
pappus: the group of appendages, usually hairs or scales, above the ovary and outside the corolla in Asteraceae (possibly a modified calyx); often persisting on the fruit and aiding in its dispersal.
parallel: of veins in a lamina, all running in the same direction and equally distant from one another, as in grass leaves. Fig. 9 F.
paraphysis: a sterile filament occurring amongst the sporangia of some ferns. pl. paraphyses.
parasite: an organism growing and feeding upon another organism (the host). A hemiparasite is partly parasitic, partly autotrophic, and has some chlorophyll.
paratype: a specimen or illustration, other than the holotype, that was cited with the original publication of a name.
parenchyma: plant tissue consisting of mature, living cells that are relatively unspecialised in function.
parietal: (1) attached to the wall; (2) of placentation, with placentas on the wall or intruding partitions of a unilocular compound ovary, Fig. 13 B.
paripinnate: term describing a pinnately compound leaf without a single terminal leaflet, and therefore usually with an even number of leaflets. Fig. 3 D. cf. imparipinnate.
partial inflorescence: a portion of an inflorescence, particularly a part sufficiently branched to show the same structural plan as the inflorescence as a whole.
patelliform: knee-shaped; shaped like a small dish, circular and rimmed.
pedate: term describing a palmately compound leaf with the lateral leaflets divided again. Fig. 3 F. cf. ternate.
pedicel: the stalk of a flower (above the subtending bract or leaf); bracteoles are sometimes present on a pedicel.
peduncle: the stalk of an inflorescence
peltate: term describing an organ with a stalk or point of attachment on its lower surface away from the margin, often umbrella-like; e.g. leaves (Fig. 4 A), scales (Fig. 15 H).
pendent (pendulous): drooping, hanging downwards; e.g. of a shrub,. Fig. 1 O; of an ovule hanging from the top of the ovary, i.e. in an apical position. Fig. 13 G.
pendulous: see pendent.
penicillate: pinnately arranged veins in which the secondary veins are conspicuous and numerous and are more or less parallel to each other, as in a feather.
penniveined: pinnately arranged veins in which the secondary veins are conspicuous and numerous and are more or less parallel to each other, as in a feather.
pentamerous: of a flower, having five parts in each floral whorl (not necessarily including the gynoecium).
pepo: a fruit with firm skin, pulpy interior, many-seeded and a single loculus, derived from an inferior ovary, e.g. a pumpkin.
perennating: (of a plant) remaining alive for several years; (of an organ) a vegetative part that assists a plant to perennate.
perennial: a plant whose life-span extends over more than one growing season. cf. biennial, annual.
perfoliate: of a sessile leaf or bract, having its base completely surrounding the stem. Fig. 4 F.
perianth: the calyx and corolla collectively; especially when they are similar, individual segments then being called tepals.
pericarp: the wall of the fruit, developed from the ovary wall. cf. endocarp, exocarp, mesocarp.
perigynous: term describing sepals, petals and stamens that are attached to the rim of a lateral or upward expansion of the receptacle, or attached to the rim of a hypanthium which is not fused to the ovary. Fig. 12 D.
perisperm: nutritive tissue within the seed which is formed outside the embryo sac, lies between the embryo sac and the testa. cf. endosperm.
pers. comm.: personal communication; information gained from other than published sources.
persistent: remaining until the part that bears it is fully matured, e.g. of floral parts remaining until fruit is mature; of a leaf base, remaining attached to the plant after the leaf or frond has been shed.
petal: a free segment of the corolla.
petaline: of the petals, e.g. petaline calyptra, the calyptra formed from petals.
petaloid: resembling a petal, especially in colour and texture.
petiole: the stalk of a leaf. adj. petiolate. Fig. 4 B.
petiolule: the stalk of a leaflet. See also terminal petiolule.
phanerogam: a plant with conspicuous reproductive parts; a plat reproducing by seeds. cf. cryptogam.
phenotype: the physical characteristics of an organism; the outward expression of characteristics conferred on an organism by its genotype. cf. genotype.
pheromone: a substance that attracts certain insects, as in the discharge from osmophores.
phloem: the tissue in the conducting system of a plant through which metabolites (products of chemical reactions in the plant) are transported. cf. xylem.
phyllary: an involucral bract of the Asteraceae, collectively the phyllaries surrounding a head form the calyculus.
phyllichnium: in family Casuarinaceae, the ridge of a branchlet article. pl. phyllichnia.
phyllode: a flattened petiole, leaf-like in appearance and function, replacing the lamina, as in many wattles.
phyllotaxy: the arrangement of leaves on a stem (when spiral, often expressed quantitatively as the fraction of the circumference of the stem that separates two successive leaves).
phylogeny: the evolutionary development of a plant group, i.e. its derivation from its ancestors and the relationship among its members. adj. phylogenetic.
phylum: a taxon of high rank, the major unit of classification. cf. division
pilose: hairy with long soft weak hairs which are clearly separated but not sparse. Fig. 14 H.
pinna: a primary segment of the lamina of a compound leaf. pl. pinnae.
pinnate: (1) (1-pinnate) of a leaf, with the lamina divided into pinnae in 2 rows along a rachis, once compound (Fig. 3 C & D) see imparipinnate, paripinnate. cf. bipinnate, tripinnate; (2) of veins, with the secondary veins arranged regularly (Fig. 9 A) cf. penniveined. adv. pinnately.
pinnately trifoliolate: of a leaf, with three leaflets arranged pinnately, i.e. the terminal petiolule usually jointed and longer than the lateral ones. Fig. 3 K. cf. palmately trifoliolate.
pinnatifid: of simple leaves or leaflets, of the lamina cut into lobes on both sides of the midrib. Fig. 5 R. cf. pinnatisect.
pinnatisect: of simple leaves or leaflets, of the lamina cut down almost to the midrib but having the segments confluent with it. e.g. as in the ultimate segments of some fern fronds. Fig. 5 S. cf. pinnatifid.
pinnule: a leaflet of a bipinnate leaf. pl. pinnules.
pistil: a free carpel or a group of fused carpels. See gynoecium.
pistillate: with a female flower.
pistillode: a rudimentary pistil present in some male flowers.
pith: the centremost tissue of a stem, often soft and spongy.
pitted: having numerous small depressions on the surface.
placenta: the part of the ovary to which the ovules are attached.
placentation: the arrangement of the placentas and the attached ovules. Fig.13.
plagiotropic: mode of growth of lateral branches, growing horizontally away from the leading shoot and maintaining a different morphology, as in some conifers. cf. orthotropic.
plano-convex: with upper surface convex, lower surface more or less flat. Fig. 10 A.
plicate: longitudinally folded. Fig. 11 I.
-ploid: suffix; multiple of a single basic set of chromosomes in the nucleus; e.g. haploid = 1 set, diploid = 2 sets; see also polyploid.
plumose: feather-like, with a central axis and fine hairs arising from it; e.g. (1) the styles in Clematis species, (2) the pappus of some Asteraceae, Fig. 15 K.
plumule: the shoot of the embryo.
pluritubulose: organs with several to many transverse as well as several longitudinal septa (seen by splitting the organ). cf. unitubulose.
pneumatophores: specialized vertical roots produced by some vascular plants which grow in water, water-logged mud or tidal swamps; the roots contain spongy tissue which enables them to exchange gases with the atmosphere through lenticels in their aerial portions, as in many mangroves.
pod: a legume or superficially similar fruit. Fig. 18 I.
pollen: the microspores of seed plants, formed in and shed from the anthers, by which time some nuclear division has taken place to form a gametophyte enclosed in the spore wall.
pollination: the transference of pollen from the anther to the stigma of flowers, and from the microsporangium to the pollen chamber of conifers and cycads.
pollinium: a mass of pollen grains cohering by means of their wavy texture or fine threads, as in Asclepiadaceae. pl. pollinia.
polygamodioecious: of plants, having bisexual and male flowers in some plants and bisexual and female flowers on others. cf. androdioecious, andromonoecious, dioecious, monoecious, polygamomonoecious, polygamous.
polygamomonoecious: of plants, having bisexual and unisexual flowers on the same plant. cf. androdioecious, andromonoecious, dioecious, monoecious, polygamodioecious, polygamous.
polygamous: having bisexual and unisexual flowers on the same plant.
polymorphic: displaying a number of varieties of form.
polypetalous: with free petals. cf. gamopetalous.
polyphyletic: composed of members that originated, independently, from more than one evolutionary line. cf. monophyletic.
polyploid: having more than two lots of the basic set of chromosomes in the nucleus. cf. diploid, haploid.
pome: a fleshy false fruit, formed from an inferior ovary, in which the hypanthium has enlarged to enclose the true fruit, as in Malaceae. Fig. 18 C.
poricidal: opening by pores, e.g. of anthers (Fig. 20 E) or capsules (Fig. 18 N).
porrect: pointed outward.
posterior: toward the axis, away from the subtending bract. cf. anterior.
praemorse: as though the end were bitten off, coarsely erose.
prickle: a hard, pointed outgrowth from the surface of a plant, involving several layers of cells, but not containing a vascular system. Fig. 14 O. adj. prickly. cf. spine, bristle.
proboscis: a snout, a surface projection.
probract: small, leaf-like structure at the base of an inflorescence in family Cucurbitaceae, usually arising opposite a tendril.
processes: outgrowths or projections from a surface.
procumbent: having stems trailing or spreading over the ground. Fig. 1 K.
proliferous: plants which bear adventitious buds on the leaves or flowers, such buds being capable of rooting and forming separate plants. e.g. bulbils, epiphyllous plantlets.
propagule: a structure with the capacity to give rise to a new plant, e.g. (1) a seed, (2) part of the vegetative body capable of independent growth if detached from the plant.
prophyll(s): the first leaf or pair of leaves of a shoot, in some monocotyledons delicate and not differentiated into blade and sheath.
prostrate: lying flat on the ground. Fig. 1 L.
protandrous: of a flower, shedding pollen before the stigma is receptive.
prothallus: the gametophyte stage of ferns and fern allies; usually flattened and delicate.
protogynous: of a flower, with the stigma becoming receptive and ceasing to be receptive before the pollen is shed.
protuberance: a prominently raised area on the surface of an organ, e.g. on bracteoles (as in family Casuarinaceae).
proximal: near to the point of origin or attachment. cf. distal.
pruinose: of a surface, having a waxy bloom that may be rubbed off. cf. glaucous.
pseudanthium: a condensed inflorescence unit in which several flowers resemble a single flower, as in Centrolepis.
pseudo-: a prefix: false; apparent but not genuine.
pseudobulb: a thickened bulb-like stem of sympodial orchids with one or several internodes.
pseudopinnate: term describing a lateral shoot resembling a pinnate leaf, i.e. a shoot with limited growth and with simple leaves arranged in 2 rows like the leaflets of a pinnate leaf.
pseudowhorled: of leaves, arranged in clusters on the stem, the clusters separated by regular intervals, usually produced behind a scaly bud. Fig. 2 G. cf. whorl.
puberulous (puberulent): a dense covering of very short soft hairs, minutely pubescent.
pubescent: a somewhat dense covering of short, weak, soft hairs. Fig. 14 B.
pulvinule: the pulvinus at the base of a petiolule.
pulvinus: the swelling at the base of the petiole, often capable of changing form to bring about movement of leaf, sometimes glandular or responsive to touch. A similar swelling near the apex of a petiole is referred to as an upper pulvinus. pl. pulvini.
punctate: marked with dots.
punctulate: minutely dotted.
pungent: (1) ending in a stiff, sharp point; (2) having an acrid taste or smell.
pustulate: covered with small blisters.
pyramidal: pyramid-shaped, broadest at or near the base.
pyrene: the endocarp and enclosed seed of a drupaceous fruit.
quincuncial: of the arrangement of corolla lobes in a bud, a variant of imbricate aestivation.
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