labellum: the distinctive median petal in Orchidaceae, usually differing in size and shape from those either side.
labiate: lipped; where the limb of a corolla or a calyx is divided into 2 parts, called an upper and lower lip.
lacerate: as if torn; irregularly cut or cleft. Fig. 8 F.
laciniate: as if cut into narrow slender teeth or lobes. Fig. 8 G.
lacuna: a gap or cavity.
lamella: a thin plate-like layer. adj. lamellose.
lamina: an expanded portion of a leaf or petal. pl. laminas.
laminate: broadened into a lamina.
lanceolate: lance-shaped; 3-6 times as long as broad and broadest below the middle and tapering to the apex. Fig. 5 I.
lateral: attached to the side of an organ, e.g. leaves on a stem.
latex: a fluid exuded from cut surfaces of the leaves and stems of some plants, usually milky, sometimes yellowish and watery, e.g. as in many species in families Moraceae and Apocynaceae.
latrorse: turned sideways; of anthers, dehiscing longitudinally on the side. cf. extrorse, introrse.
lax: loose, not compact.
leaf: an organ borne on the stem of a plant, usually expanded and green; typically consisting of the more or less expanded lamina and the petiole or leaf stalk.
leaflet: one of the ultimate segments of a compound leaf. cf. pinna, pinnule.
leaf-opposed: arising from the stem opposite a leaf-base, as do some tendrils or inflorescences.
lectotype: a specimen selected from among those cited with the original description to serve in place of a holotype where the holotype is missing or destroyed, or where no holotype was designated.
legume: (1) a pod, a dry dehiscent fruit formed from one carpel and having two longitudinal lines of dehiscence, Fig. 18 I; (2) a member of the family Fabaceae.
lemma: the lower of two bracts enclosing the flower of a grass; male lemma - lemma enclosing a male flower; sterile lemma - an empty lemma.
lenticel: a small raised corky spot or line appearing on young bark, through which gaseous exchange occurs.
lenticular: a 3-dimensional shape like a doubly convex lens, circular in outline.
lepidote: covered with small, membranous scales.
leptomorph: applied to the rhizome system of some bamboos with indeterminate growth in which the aerial shoots arise laterally from an extensive rhizome system.
leptosporangiate: of ferns, having sporangia with walls consisting of a single layer of cells; the sporangium originating from a single cell. cf. eusporangiate.
liana (liane): a woody climbing plant.
lignified: converted into wood, hardened.
lignotuber: a woody swelling, partly or wholly underground, at the base of certain plants and containing numerous cortical buds, as in many eucalypts (Fig. 1 H); see mallee.
ligulate: (1) with a ligule; (2) of ray florets in Asteraceae, with a strap shaped limb.
ligule: (1) a variously shaped appendage facing towards the base of a leaf (especially in grasses), petiole, or perianth segment; (2) the strap shaped corolla lobe or limb in ray florets of Asteraceae.
limb: the expanded and usually flat portion of an organ, e.g. of a petal, or the expanding part of the corolla above a corolla tube.
linear: long and narrow with more or less parallel sides, more than 12 times as long as broad. Fig. 5 B.
linear-lanceolate: more than 12 times as long as broad and broadest in the lowest third and tapering to the apex.
linear-oblanceolate: more than 12 times as long as broad and broadest in the upper third and tapering to the base.
lineolate: marked with fine or obscure lines.
lithophyte: a plant growing on a rock, e.g. some orchids. cf. epiphyte
littoral: on or growing near the seashore.
loculicidal dehiscence: in capsules, dehiscence in median lines through the walls of the loculi rather than at the partitions between the loculi or at the placentas. Fig. 18 L. cf. septicidal.
loculus: a more or less closed cavity, containing the pollen in anthers (Fig. 20 C) and the ovules in an ovary (Fig. 13). pl. loculi.
lodicule(s): one or two scale-like structures below the stamens and ovary of a grass and regarded as a reduced perianth.
lomentum: a legume that breaks transversely into usually 1-seeded indehiscent articles when mature. Fig. 18 J. cf. schizocarp.
long-creeping: in ferns, a rhizome that elongates rapidly so that the fronds are usually well separated from each other. cf. short-creeping.
longitudinal: of venation, with several veins extending from the base to the apex of the lamina but the veins not more or less parallel with each other. Fig. 9 E.
lorate: of leaves, strap-shaped (moderately long with the two margins parallel).
lyrate: lyre-shaped, of pinnatifid or pinnatisect leaves with the terminal lobes much larger than the basal ones. Fig. 5 P.
Malesia: a phytogeographic region; including the Malay Peninsula, Malaysia, the Philippines, Indonesia and New Guinea.
mallee: (1) a growth form in which many stems arise from a lignotuber, usually applied to eucalypts; (2) of a plant community dominated by mallee eucalypts.
mangrove: a shrub or small tree growing in salt or brackish water and often with pneumatophores or aerial roots.
marcescent: withering without falling off.
marginal: (1) at or very close to the margin; (2) of placentation, with the placenta along the margin of a simple ovary, as in many legumes, Fig. 13 A.
maritime: belonging to the sea; confined to the sea-coast.
marsh: a waterlogged area; swampy ground without trees.
mealy: covered with coarse flour-like powder.
medifixed: attached by or at the middle, e.g. of anthers, attached to the filament at the middle of the connective.
megasporangium: a sporangium producing megaspores, = ovule in flowering plants.
megaspore: the spore in heterosporous plants that gives rise to a female gametophyte and is generally larger than the microspore; the spore usually not shed but remaining on the parent plant and developing in situ. cf. microspore.
megasporophyll: a specialised leaf upon (or in the axil of) which one or more megasporangia are borne. cf. microsporophyll.
meiosis: the two-stage division of a diploid nucleus in which the genetic recombination occurs and the number of chromosomes characteristic of the species is halved prior to the production of the sexual gametes; this process takes place once in every sexual life cycle.
membranous: thin and translucent.
mentum: a chin-like extension at the base of some orchid flowers formed by the column foot and the bases of the lateral sepals.
mericarp: one segment of a fruit that breaks at maturity into units derived from the individual carpels, sometimes called a coccus. Fig. 18 H & P. See schizocarp.
meristem: a growing region of a plant in which cells divide to produce new cells.
-merous: a suffix indicating that the number of parts in each floral whorl is divisible by the same basic number, e.g. a 5-merous flower is one with the number of sepals, petals and stamens divisible by 5; e.g. 5 sepals, 10 or 5 petals, and 5, 15 or 20 stamens. The number of carpels and their styles or stigmas often does not conform to the basic number.
mesic: requiring abundant water.
mesocarp: the fleshy part of the wall of a succulent fruit; the middle layer of the pericarp in a drupe.
mesomorphic: soft and with little fibrous tissue, but not succulent. cf. scleromorphic.
mesophyll: photosynthetic tissue of a leaf; of vegetation, characteristic of moist habitats and with soft, fairly large leaves predominating.
microphyllous: having small leaves that are usually hard and narrow.
micropyle: the small canal through the integuments (outer layers of tissue) of an ovule, usually at the point furthest away from the funicle (ovule stalk), persisting as a pore in the seed coat.
microspecies: segregate species of a larger species or species-aggregate, e.g. see Rubus fruticosus.
microsporangium: the sporangium producing the microspores, within the anthers in angiosperms.
microspore: the spore in heterosporous plants that gives rise to a male gametophyte and is generally smaller than a megaspore; microspores are shed at maturity. cf. megaspore, pollen.
microsporocarp: a body containing the microsporangium, e.g. as in some ferns.
microsporophyll: a specialised leaf upon (or on the axil of) which one or more microsporangia are borne
midrib: term applied to the midvein or primary vein, especially when it is prominently raised or depressed.
midvein: the primary vein which runs from the base to the apex of the lamina, usually the most prominent vein, from which arise the secondary or lateral veins.
minute: very small, usually less than 1 mm long.
mitra: a pointed cap or hood.
monadelphous: of stamens, with their filaments fused into one group, as in many Malvaceae. Fig. 20 G. cf. diadelphous.
moniliform: of a pod or other organ: constricted , so as to resemble a necklace of beads; e.g. hairs, Fig. 15 E.
mono-: a prefix, one: as in monotypic, a genus with 1 species.
monochasium: a cyme with the branches arising singly. Fig. 17 E. cf. dichasium.
monochlamydeous: of a flower, having only one whorl of perianth parts. cf. dichlamydeous.
monocotyledons: a major group of angiosperms, characterized by the embryo usually having one cotyledon (seed leaf). cf. dicotyledons.
monoecious: having male and female flowers on the same plant.
monophyletic: derived from a single ancestral line. cf. polyphyletic.
monopodial: with a persistent terminal growing point producing many lateral organs progressively. cf. sympodial.
monotypic: of a genus, having only one species. cf. unigeneric.
motile: actively moving; self-propelled.
mucilage: a slimy, gummy substance sometimes secreted by hairs or glands. adj. mucilaginous.
mucro: a sharp, usually suddenly constricted, apical point.
mucronate: having a mucro. Fig. 6 K.
mucronulate: a small mucro on obtuse apex.
multicellular hairs: hairs consisting of more than 1 cell.
multiple fruit: a cluster of fruits produced from more than one flower and appearing as a single fruit, often on a swollen axis, as in Moraceae. Fig. 18 Y & Z. e.g. syncarp, syconium. cf. aggregate fruit.
muricate: of a surface, rough with pointed protuberances or short hard tubercles. Fig. 16 B.
muriculate: minutely muricate, rough with minute, short, hard points.
muticous: blunt, awnless, lacking a point.
mycorrhiza: a symbiotic association between a fungus and a plant root.
naked: of flowers, without a perianth; of sporangia, not covered with an indusium; of seeds, not enclosed in an ovary, exposed on the surface of a sporophyll.
native: naturally occurring in the area, but not necessarily confined to it. cf. endemic.
naturalized: originating elsewhere but established and reproducing itself as though native to the area.
nectar: a more or less sweet fluid secreted from a specialized gland or nectary.
nectary: a gland that secretes nectar.
neotype: a specimen selected to serve in place of a holotype where none of the material to which the name was originally applied is known to have been preserved.
nerve: a vein, usually applied to rather straight and strong veins.
net veins (reticulate): forming a network or reticulum; e.g. of veins, Fig. 9 H.
nocturnal: of flowers, opening only at night. cf. diurnal.
node: the level of a stem at which one or more leaves arise.
nodulose: with small swellings or knobs.
nomenclature: the names and naming of things; often restricted to the correct usage of scientific names in taxonomy.
nom. cons.: (nomen conservandum, Latin) a name for a taxon that has been formally accepted as the correct name even though it is contrary to the usual principles of botanical nomenclature.
nom. illeg.: (nomen illegitimum, Latin) a name which, at its time of publication, was superfluous (because the taxon to which it was applied had already been named) or had already been applied to another plant.
nom. nud.: (nomen nudum, Latin) a name not published in accordance with the principles of botanical nomenclature (usually without a diagnosis or description of the entity to which it applies and without reference to either); such a name should not be used.
non: (Latin) not of.
nut: a dry indehiscent one-seeded fruit formed from two or more carpels. Fig. 18 T.
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