Glossary - general

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Macropodal embryo – with an enlarged hypocotyl forming the larger part of the whole embryo

Maculate – with spots

Male – staminate – Opposite: female/pistillate

Malleate – (Euphorbiaceae) as if hammered, with many shallow circular depressions

Malpighiaceous hair – a unicellular T-shaped hair (as seen from the side) with a short stalk and often with a fusiform outline (as seen from above)

Malpighian cell – (Fabaceae) a macrosclereid present in the testa; a Malpighian cell layer, a palisade epidermal layer of vertical thick-walled Malpighian cells, is often responsible for the water-impermeability and hardseededness of many Fabaceae seeds

Malpighian layer – see Malpighian cell

Malvoid leaf tooth – with the medial vein forming a non-glandular persistent apex, not associated with lateral veins

Mamelon – placental nucellar complex; an undifferentiated mass of tissue in the female flowers of many mistletoes (Santalales), in which the two megagametophytes are embedded; in this case no true ovule is developed

Mamillate, mammillate – with nipple-like processes

Mammate – conical, with a rounded apex

Mangrove – coastal swamp of the tropics, regularly inundated by tidal salt water; also, a tree species adapted to swamps like this, with special adaptations (i.a. breathing roots)

Marcescent leaf or corolla – after withering, remaining attached to the plant, not abscissing

Marginal – at or near the edge

Marginal axial parenchyma – parenchyma present at the beginning of growth rings (initial parenchyma, rare) or as a band at the end of a growth ring (terminal parenchyma); parenchyma bands which form a more or less continuous layer of variable width at the margins of a growth ring or are irregularly zonate

Marginal placentation – ventral placentation; the single elongated placenta is situated on one side of the simple ovary

Margo (of bordered pits) – the remaining unthickened part of the pit membrane outside the torus

Marine – growing in the sea

Maritime – associated with the sea or coast

Marmorate – with coloured veins or patches, as in some marbles

Massula (pl. massulae) – (Orchidaceae) pollen mass consisting of a number of pollen tetrads, which is derived from a single archesporial cell

Mat-forming – low-growing plants growing so close together that they form a continuous cover, or prostrate and rooting at the nodes (in which case a single plant can form a mat)

Matt, matte – dull, not shine – Opposite: shiny, glossy

Matted – closely intertwined, forming a carpet

Mature fruit – when fully grown and ripe, ready to distribute seeds – Opposite: unripe

Median – situated in the middle

Median placentation – see Laminar-median placentation

Medifixed hair or anther – attached near the middle

Medulla – pith; spongy storage tissue, usually in the centre of the stem/branch or the root; the medulla consists of loosely spaced parenchyma cells

Medullary – pertaining to the medulla (pith)

Medullary plate (of leaf) – vascular bundles present inside the siphonostele of a leaf

Medullary ray – plates of tissue /usu. parenchymatous) radiating through the vascular cylinder from the pith to the cortex

Medullated – provided with a medulla (pith), e.g. a stele

Megagametophyte – the female gametophyte of the haploid generation

Megasporangium – nucellus; the sporangium in which megaspores develop

Megaspore – the larger-sized spore in heterosporous plants; the one that produces female gametes – Opposite: microspore

Megasporocyte – megaspore mother cell; a diploid cell which undergoes meiosis and thus produces four haploid megaspores (megasporogenesis)

Megasporogenesis – see Megasporocyte

Membrane – thin, film-like, flexible, often translucent

Membranous, membranaceous – like a membrane: flexible and thin, usually also translucent

Mentum (of flower) – (Orchidaceae) a chin-like extension at the base of the flower, made up of the column foot and the lateral sepals

Mericarp – seed-containing parts of a fruit, each usually derived from a carpel, which usually dehisce independently from each other when ripe

Mericarpic – pertaining to mericarps

Meridionosulcate pollen grain – with a meridionosulcus

Meridionosulcus (of pollen grain) – a meridional (zonal) sulcus

Meristele – in a monostelic stem, a portion of the stele received by each leaf

Meristem – undifferentiated tissue capable of division

Mesarch (of primary xylem) – with the primary xylem maturing from the centre towards the interior and exterior of the stem; with the metaxylem developing both internal and external to the protoxylem

Mesocarp – the middle layer of the fruit wall, often distinguished as such when fleshy or succulent

Mesochile (of flower) – (Orchidaceae) the mid-portion of a lip that is divided into three distinct portions

Mesocolpium – the meridional segment between two colpi, which extends to the poles

Mesocotyl – the internode between the haustorium/scutellum and the coleoptiles in a monocot embryo or seedling; an epicotyl which is congenitally fused with the base of the coleoptile

Mesophyll – the undifferentiated chlorophyllous parenchymatic ground tissue in the leaf between the two layers of epidermis; the mesophyll consists of several layers of chlorenchyma cells; cells of the mesophyll are responsible for the photosynthesis

Mesophyte – terrestrial plant which is adapted to neither a particularly dry nor particularly wet environment, but instead to a mesophytic habitat

Mesotesta – the middle part of the testa

Metastipule – see Pseudostipule

Metatracheal axial parenchyma – see Apotracheal axial parenchyma

Microechinate tectum – echinulate tectum; with echinae smaller than 1 µm

Microgranulate surface – minutely granulate

Micropunctate – with minute dots or translucent glands

Microreticulate tectum – with a reticulate ornamentation consisting of muri and lumina smaller than 1 µm

Micropyle – (1) (of ovule) an opening in the integuments, through which the pollen tube enters; (2) (of seed) an opening through which the radicle usually emerges on germination

Micropylar – pertaining to the micropyle

Micropylar collar – (Zingiberales) a cylindrical ridge-like thickening, which surrounds the micropyle and is formed from the outer integument and penetrates the micropylar part of the megasporangium; the micropylar collar is usually visible on the seed

Microspore – pollen grain in seed plants; the smaller-sized spore in heterosporous plants; the one that produces male gametes – Opposite: megaspore

Microsporangium – a sporangium which produces microspores

Microsporocyte – pollen mother cell, microspore mother cell; a diploid cell which undergoes meiosis and thus produces four haploid microspores (microsporogenesis)

Microsporogenesis – see Microsporocyte

Midrib – the main vascular supply and support structure of a simple leaf-blade (lamina); continuation of the petiole, running the full length of the leaf

Minute – very small

Mitriform – cap-shaped and ending in a point, as in the mitre of a bishop

Monad (of pollen grains) – solitary pollen grain, as opposed to dyad, tetrad or polyad

Monadelphous stamens – in one bundle and connate by the filaments (e.g. Malvaceae)

Monarch stele – containing a single file of tracheids and sieve elements within a ring of pericycle cells (i.a. in hair roots)

Moniliform – like a string of beads, or constricted at regular intervals

Monimioid leaf tooth – with the secondary or tertiary vein ending in an opaque persistent glandular cap, not associated with lateral veins

Monocarp – annual or other plant that flowers and fruits only once, then dies

Monocarpellate – with a single carpel; fruit consisting of a single carpel

Monocarpic – adjective of monocarp

Monochasial – adjective of monochasium

Monochasium – (1) cyme with a single main axis; (2) inflorescence with a terminal flower and one floral prophyll (bracteole) subtending a lateral flower; for compound monochasium (where the lateral part branches further) see Cincinnus

Monochlamydeous flower – having one whorl of perianth segments (i.e. only the calyx, or only the corolla)

Monococcous – a fruit which is usually several-lobed, with but a single lobe or unlobed, usually through abortion of all but one carpel

Monocolpate pollen grain – with a single colpus

Monocotyledon – a plant with a single cotyledon (seed leaf); a natural group also characterized by, i.a., lack of secondary xylem, the presence of parallel veins and trimerous flowers

Monoecious – with separate male and female flowers or inflorescences on the same plant

Monomorphic – of one type only, not of several types

Monopodial – branching system with the main axis growing indefinitely at the apex; secondary shoots may develop below the growing point; monopodial inflorescences are generally known as racemose, and include, e.g., racemes, panicles, and (by contraction of the rachis) the true umbel and the corymb; sympodial inflorescences are generally known as cymose and include, e.g., the monochasium, the dichasium, cincinnus and false umbel

Monoporate pollen grain – with a single pore

Monosporic megagametophyte – developing from a single megaspore nucleus from the megaspore tetrad

Monostelic stem – with a single stele

Monosulcate pollen grain – with a single sulcus (furrow-like aperture)

Monosulcoidate pollen grain – with a single sulcus-like aperture

Monosymmetrical– see Zygomorphic

Monotelic inflorescence – each lateral branch ends in a flower

Monothecal anther – with a single theca

Monotropoidal mycorrhiza – penetrating the outer cortical cells in the hair roots, although these are covered by a Hartig net, in which the hyphae form peg-like invaginations in the cell wall

Monoulcerate pollen grain – with a single ulcus

Mottled – with spots or blotches of different colour

Mucilage – slime or jelly-like exudate, chemically composed of proteinaceous carbohydrate

Mucilage cell, mucilaginous cell – a type of idioblast containing and secreting mucilage (secreted in golgi vesicles); mucilage cells lack a suberized cell layer

Mucilaginous – slimy

Mucro – a short sharp terminal point

Mucronate – ending abruptly in a short stiff point

Mucronulate – ending in a very short stiff point

Multi- – many-

Multifid – split into many parts

Multifolliculus (pl. multifolliculi) – follicetum; a compound fruit, in which each carpel of the flower gives rise to a single follicle, these being arranged in spiral or in one or several whorls

Multilacunar node – with more than three leaf gaps left in the central vascular cylinder when corresponding numbers of leaf traces depart

Multilocellate anther – with several or numerous secondary compartments delimited by transverse septa

Multiplicative testa – multiplicative integuments; divisions (after fertilization) in the primary cell layers of the outer integument produce several or numerous cell layers in the final stage

Multiseriate structure – arranged in many rows, e.g. ovules on a placenta

Multiseriate wood ray – two (biseriate) or more (pluriseriate) cells wide at the widest point

Muricate – rough, with short hard pointed protuberances

Muriculate – minutely muricate

Murus (pl. muri; of pollen grains) – ridge which is part of the ornamentation and, i.a., separates the lumina in a reticulate pollen grain or the striae in a striate pollen grain

Muticous – blunt, without a point

Mycoheterotrophy – when a mycotrophic plant parasitizes fungi, receiving all its carbon, nutrients and water from the fungus

Mycorrhizal – with symbiotic fungi in the roots, or clothing the roots; usually forming a mutualistic association between plant and fungus

Myriophyllin cell – a specialized cell containing tannins etc. (in, e.g., Typhaceae)

Myrmecochorous – dispersed by ants

Myrmecodomatia – believed to be visited or inhabited by ants

Myrmecophilus plant or species – with an affinity for ants, sometimes with specialized structures thought to harbour or feed ants

Myrosin cell – cell storing myrosin grains containing myrosinase, an enzyme catalyzing the hydrolysis of glucosinolate; in the presence of water, myrosinase cleaves off the glucose unit from a glucosinolate, whereas the remaining molecule immediately converts to a thiocyanate, an isothiocyanate or a nitrile, which are defensive substances

Myxotesta – a mucilaginous testa