Glossary of Botanical Terms - M

M

Macaronesia

a biogeographic area encompassing the islands off the coast of NW Africa and Europe, including the Azores, Canaries, Cape Verde Islands and Madeira.

Malaysia

Malay peninsula and North Borneo.

Malesia

a biogeographic region comprising Malaysia, Indonesia, New Guinea, and the Philippines.

mallee

growth habit in which several woody stems arise separately from a lignotuber; a plant with such a growth habit; vegetation characterized by such plants.

mangrove

a shrub or small tree growing in salt or brackish water, usually characterized by pneumatophores.

margin

the edge, as in the edge of a leaf blade.

marginal

occurring at or very close to the margin.

marsh

a waterlogged area; swamp.

mast

the edible vegetative or reproductive part produced by woody species of plants, i.e. trees and shrubs, that wildlife species and some domestic animals consume.

mealy

covered with coarse, floury powder, sometimes due to collapsed hairs.

megaspore

the larger of two kinds of spores produced by a heterosporous plant giving rise to the female gametophyte; compare microspore.

megastrobilus

the larger of two kinds of cones or strobili produced by gymnosperms, being female and producing the seeds; compare microstrobilus.

membranous

thin, translucent and flexible, seldom green.

mericarp

one segment of a fruit (a schizocarp) that splits at maturity into units derived from the individual carpels, or a carpel, usually 1-seeded, released by the break-up at maturity of a fruit formed from 2 or more joined carpels.

meristem

a group of actively dividing tissues.

mesic

moist, avoiding both extremes of drought and wet; pertaining to conditions of moderate moisture or water supply; applied to organisms (vegetation) occupying moist habitats.

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); sarcocarp.

mesomorphic

soft and with little fibrous tissue, but not succulent.

mesophyll

1. mesophyll tissue, photosynthetic tissue of a leaf, the central tissues between the upper and lower epidermis.

2. in ecology, the blade of a leaf or leaflet that has a surface area 4500–18225 mm2; A plant, or vegetation, that has mesophyll (sized) leaves.

mesophyllous

(of vegetation) of moist habitats and having mostly large and soft leaves.

mesophyte

a plant thriving under intermediate environmental conditions of moderate moisture and temperature, without major seasonal fluctuations.

microspore

the smaller of two kinds of spores produced by a heterosporous plant; compare megaspore.

microstrobilus

the smaller of two kinds of cones or strobili produced by gymnosperms, being male and producing the pollen; compare megastrobilus.

midrib

the central, and usually most prominent, vein of a leaf or leaf-like organ; midvein.

midvein

see midrib.

monad

a single individual that is free from other individuals, not united with them into a group. The term is usually used for pollen to distinguish single grains from tetrads or polyads.

moniliform

resembling a string of beads.

monochasium

a cymose inflorescence with the branches arising singly; cf. dichasium.

monocots

abbreviation of monocotyledons.

monocotyledon

a flowering plant whose embryo has one cotyledon (seed leaf); compare dicotyledon.

monoecious

of vascular plants, where the male and female reproductive structures are in separate flowers but on the same plant; of inflorescence, including unisexual flowers of both sexes; cf. dioecious.

monograph

of a group of plants, a comprehensive treatise presenting an analysis and synthesis of taxonomic knowledge of that taxon; the fullest account possible (at the time) of a family, tribe or genus. It is generally worldwide in scope and evaluates all taxonomic treatments of that taxon including studies of its evolutionary relationships with other related taxa, and cytological, genetic, morphological, palaeobotanical and ecological studies. The term is often incorrectly applied to any systematic work devoted to a single taxon. Compare revision.

monotypic

containing only one taxon of the next lower rank, e.g. a family with only one genus, or a genus that includes only a single species.

morphology

the shape or form of an organism or part thereof.

mucro

a sharp, short point.

mucronate

terminating in a mucro.

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; cf. aggregate fruit.

muricate

covered with short hard protuberances.

mutation

an abrupt and inexplicable variation from the norm, such as the doubleness in flowers, changes in colour, or habit of growth.