page_title: Glossary of botanical terms
section_title: M
hierarchical_section_title: Glossary of botanical terms / M
caption_attribution_description: Français&#160;: Paxillus involutus cultivé sur milieu PDA (potato dextrose agar).
context_page_description: This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology.
context_section_description: maculate
  Spotted; marked with spots.
  male flower
  See staminate flower.
  mallee
  A growth habit in which several woody stems arise separately from a lignotuber; a plant with such a growth habit, e.g. many Eucalyptus species; vegetation characterized by such plants.
  mangrove
  Any shrub or small tree growing in salt or brackish water, usually characterized by pneumatophores; any tropical coastal vegetation characterized by such species.
  margin
  The edge of a structure, as in the edge of a leaf blade.
  marginal
  Occurring at or very close to a margin.
  marsh
  A waterlogged area or swamp.
  mast
  Edible fruit and nuts produced by woody species of plants (e.g. acorns and beechmast) which is consumed on the ground by wildlife species and some domestic animals.
  mealy
  Covered with coarse, floury powder.
  medulla
  1.  In a lichen, the typically undifferentiated tissue underneath the cortex of the thallus, or between the upper and lower cortex if both are present. The medulla is analogous to the tissues underneath the epidermis (skin) of a leaf. The uppermost region commonly contains most of the photobionts.
  2.  pith. See also medullary rays in wood.
  megasporangium
  the larger of two kinds of sporangium produced by heterosporous plants, producing large spores that contain the female gametophytes. Compare microsporangium.
  megaspore
  the larger of two kinds of spores produced by a heterosporous plant, giving rise to the female gametophyte. Compare microspore.
  megasporophyll
  in hetersoporous plants, a modified leaf bearing one or more megasporangia. Compare microsporophyll.
  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
  Any actively dividing plant tissue.
  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.  The parenchyma tissues between the upper and lower epidermis. They vary in function, but usually include the photosynthetic tissue of a leaf
  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.
  micropyle
  Opening at apex of ovule.
  microsporangium
  The smaller of two kinds of sporangium produced by a heterosporous plant, producing microspores that contain the male gametophyte. Compare megasporangium.
  microspore
  The smaller of two kinds of spores produced by a heterosporous plant. Compare megaspore.
  microsporophyll
  In heterosporous plants, a modified leaf bearing one or more microsporangia. Compare megasporophyll.
  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
  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.
  monocarpic
  Flowering and setting seed only once before dying. See also semelparous.
  monochasium
  A cymose inflorescence with the branches arising singly. Compare dichasium, pleiochasium.
  monocot
  An abbreviati
caption: Fungal mycelium grown in culture dish
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