Australian Biological Resources Study
Compiled by A.McCusker
macrospore: = megaspore.
mallee: a growth habit in which several woody stems arise separately from a lignotuber (usually applied to shrubby eucalypts); a plant having the above growth habit; vegetation dominated by such plants.
mammillate: having small nipple-shaped projections.
marcescent: withering without falling off.
marginal: occurring at or very close to the margin. > image <
medifixed: attached by or at the middle, e.g. of anthers,with filament attached at the middle of the connective. cf. basifixed, versatile.
megagametophyte: a plant body or cell lineage, formed by vegetative growth of the megaspore, that produces the female gametes of a heterosporous plant.
megasporangium: the larger of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant.
megaspore: the larger of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the female gametophyte.
megasporophyll: a specialised leaf upon which (or in the axil of which) one or more megasporangia are borne.
meiosis: the two-stage division of a diploid nucleus, occurring once in every sexual life cycle, in which gene recombination occurs and the number of chromosomes characteristic of the sporophyte plant is halved prior to the production of gametes.
mellitophily: an insect-flower pollination syndrome involving bees.
mentum: in Orchidaceae, a spur formed by extension of the base of the column.
mericarp: one segment of a fruit that breaks at maturity into units derived from the individual carpels. cf. schizocarp. > image <
meristem: growing regions of a plant in which cells that have retained their embryonic characteristics, or have reverted to them secondarily, divide to produce new cells.
-mery: the number of parts per whorl that characterises a particular flower (generally constant for the perianth whorls and less often for the whorl(s) of stamens also). adj. merous.
mesocarp: the fleshy portion of the wall of a succulent fruit inside the skin and outside the stony layer, if any, surrounding the seed(s).
mesophyll: photosynthetic tissue of a green plant; of vegetation, characteristic of moist habitats and with soft, fairly large leaves predominating; a leaf with an area within the approximate range 20-180 sq. cm.
microgametophyte: a plant body or cell lineage, formed by vegetative growth of the microspore, that produces the male gametes of a heterosporous plant.
microphyll: a small leaf.
micropyle: a small canal through the integument(s) of an ovule, persisting as a pore in the seed coat.
microsporangium: the smaller of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant.
microspore: the smaller of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the male gametophyte.
microsporophyll: a specialised leaf upon which (or in the axil of which) one or more microsporangia are borne.
midrib: the central, and usually the most prominent, vein of a leaf or leaf-like organ. cf. costa. > image <
monadelphous: of stamens, united by their filaments into one bundle. cf. diadelphous, syngenesious.
moniliform: cylindrical but constricted at regular intervals like a string of beads.
monocarpic: flowering and fruiting only once during its life span.
monochasium: a cymose inflorescence with the branches arising singly. cf. dichasium. > image <
monochlamydeous: of a flower, having only one whorl of perianth parts. cf. dichlamydeous.
monoclinous: having male and female reproductive organs in the same flower. cf. diclinous.
monocotyledon: a flowering plant whose embryo has only one cotyledon (seed leaf). cf. dicotyledon.
monoecious: having the male and female reproductive structures in separate flowers but on the same plant. cf. dioecious. > image <
monophyletic: derived from a single ancestral line. cf. polyphyletic.
monopodial: of growth, with a persistent terminal growing point producing many lateral organs successively; of a stem, growing in the above manner. cf.
monotypic: containing only one taxon of the next lower rank, e.g. applied to a family containing only one genus. cf. polytypic.
morphocline: a graded series of character states of an homologous character.
morphology: the form and structure of an organism or part of an organism; the study of form and structure.
motile: actively moving; self-propelled.
mucilage: slimy material exuded by certain plants or plant organs. adj. mucilaginous.
mucro: a sharp, abrupt terminal point. adj. mucronate.
mucronulate: with a very small mucro; diminutive of mucronate.
multiplanar: of divided leaves, with the lobes held in several to many planes.
muricate: rough on the surface; covered with short, hard tubercles or hard outgrowths of the epidermis. > image <
muriculate: rough with minute, short, hard points.
muticous: pointless, blunt, awnless.
mycorrhiza: a symbiotic union between a fungus and a plant root.