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Term	Definition
Lithophyte	A plant growing on rocks.
Liverwort life cycle	Referring to the alternation of generations between the gameophyte (haploid) and sporophyte (diploid) stages of a liverwort. The most conspicuous stage of the life cycle is the gametophyte generation whereas the sportophyte generation is small and inconspicuous.
lobe (lobed, lobate)	A rounded projection arising from the margin or base of two dimensional structures such as leaves and bracts.
Lóbulo corolino	Es cada uno de los segmentos más o menos libres que están en la porción terminal de una corola gamopétala (o simpétala)
Locule	A chamber or cavity, such as that of an ovary or fruit that contains the ovule(s) or seed(s).
Locule	A chamber, such as that of an ovary or fruit, that contains the ovule(s) or seed(s), respectively.
Locule orientation	Locule orientation with the longest axis of a locule to the central axis of an ovary as seen in a medial longitudinal section.
Locule orientation horizontal	A locule oriented with the greatest length more-or-less at right angles to the long axis of the ovary, i.e., at a right to the upper/lower septum as seen in longitudinal section.
Locule orientation oblique	A locule with the greatest length more-or-less paralleling the long axis of the ovary, i.e., parallel to the upper/lower septum as seen in longituindal section.
Locule orientation vertical	A locule with the greatest length more-or-less paralleling the long axis of the ovary, i.e., parallel to the upper/lower septum as seen in longituindal section.
Locule width at apex	The position at which the locule's greatest width is near the apex of the locule as viewed in a medial longitudinal section.
Locule width at middle	The position at which the locule's greatest width is in the middle of the locule as viewed in a medial longitudinal section.
Locule width throughout	The position at which the locule's greatest width is equal through much of the locule as viewed in a medial longitudinal section.
Loculicidal capsule	A dry, dehiscent fruit that opens in the middle of the locule. Compare with septicidal capsule.
Lodicule	A small, colorless scale appressed to the ovary of most Poaceae that may represent a vestige of the perianth.
Loment	A type of legume fruit in which each single-seeded segment breaks away from adjacent segments; e.g., in Desmodium (Fabaceae).
Lomentiform	Like a loment.
Longitudinal section	A cut along the long axis of an organ but not necessarily through the middle of the organ. Compare with medial section.
Lorate	Referring to a two dimensional shape in which the greatest width extends throughout a middle zone at least one-third the length of the blade (in this zone the margins are more-or-less parallel) and the length to width ratio is 6:1 to less than 10 . Same as strap-like.
Loriforme	Con forma de cinturón. Se refiere a la forma de una lámina de una hoja, que es larga, angosta, plana y cuyas márgenes son paralelas
Lower septum	A wall-like partition of a locule located basally to an articulation (often only seen as a thin line), as seen in longitudinal section, that separates it from an upper septum.
Lower/upper septum	Referring to the combined lengths of the lower and the upper septa as seen in longitudinal sections. The two septae are divided by a septal articulation. The lower septa gives rise to the placenta and the upper septum develops into the columella of the fruit.
Lower/upper septum articulation	A joint between the lower septum and the upper section as seen in a longitudinal section of the ovary.
Lumper	A person (usually a plant taxonomist) that recognizes species of plants with considerable morphological variation included in their concept of species. This often results in placing other names, which may even represent valid species in themselves, in synonymy of the name used by the author for the species being described, this is called lumping species.
Lycopod	Referring to a vascular plant group that does not produce seeds. Lycopodium, Isoetes, and Selaginella are in this group but belong to different orders. Lycopodium is homosporous and the other two genera are heterosporous.
Macropodial embryo	A solid embryo without differentiated cotyledons; e.g., in Lecythis spp. (Lecythidaceae) and Monstera spp. (Araceae).
Macula (maculate)	A spot or blotch (a structure with spots or blotches).
Macula (pl. = maculae, adj. = maculate)	A spots or a blotches, usually leaves, with a color other than green (often white)..
Male flower	Referring to unisexual flowers with functional stamens but without functional gynoecia (pistillodes may be present). Same as pistillate flower.
Marcescent	Withering but persisting; e.g., a wilted corolla that persists on the fruit.
Marginal leaf vein	A leaf vein that runs more-or-less parallel to the margin of a leaf.
Marginal placentation	A type of parietal placentation in which the ovules arise along the margins of the carpel. Compare with laminar placentation; see placentation.
Marginicidal dehiscence	See septicidal and septifragal dehiscence.
Medial longitudinal section	A cut along the long axis of a flower such that the style is also cut lontidutinally.
Medial section	A cut along the long axis and through the middle of an organ. Compare with longitudinal section.
Megagametophyte	The female gametophyte of angiosperms (flowering plants). Same as embryo sac.
Mericarp	One of the units of a schizocarp. The mericarps split from the schizocarp but the mericarps are not dehiscent..
Merous	Referring to a fixed number of parts of a given organ, e.g., a flower that has 5 sepals, 5 petals, etc is 5-merous.
Mesocarp	The middle layer of the fruit wall. Compare with pericarp.
Metamorphosis	Change in the morphology and habits of an animal as a part of its normal life cycle, e.g., the changes in a butterfly as it develops from an egg to a chrysalis (= pupa), and finally to an adult or a tadpole that develops into a frog.
Microhabitat	A specialized habitat usually created by living organisms such as trees; e.g., the habitats found within the crown or along the trunk of a tree.
Micropyle	An opening in the integuments of the ovule through which the pollen tubes generally penetrate.
Micropyle	An opening in the integuments of the ovule through which the pollen tubes generally penetrate.
Midnerve	Same as midrib but used less frequently.
Midrib	The primary vein of a leaf, bract, sepal, or petal. Same as costa, midnerve, midvein, and primary vein.
Midrib	Referring to the princiipal or primary vein of a leaf blade that runs from the base of the leaf blade along the middle to the apex of the leaf blade.
Midrib plane adaxially	A midrib rib that is neither salient or impressed toward the base of the adaxial side of the leaf blade, i.e., it is flat with the leaf blade surface.
Midvein	Same as midrib but used less frequently.
Modified steady state phenology	A flowering strategy in which a few flowers are produced each day over long periods of time but for shorter periods than in steady state species.
Monad	A pollen grain that occurs singly. Compare with tetrad.
Monad	Referring to pollen grains that occur singly, i.e., they separate immediately after meiosis.
Monadelphous	Referring to stamens united by their filaments into a single group.
Monocarp	A unit of the fruit of apocarpous Annonaceae (e.g., Guatteria spp. and Unonopsis spp.), Menispermaceae, Monimiaceae, Ochnaceae, and Simaroubaceae..
Monocarpy (monocarpic or monocarpous)	Referring to plants that die after a single episode of flowering and fruiting; e.g., many bambusoid Poaceae and Tachigali (Fabaceae). Same as hapaxanthic and semelparic and opposite of iteroparic, pleionanthic, or polycarpic.
Monocliny (monoclinous)	A species with functionally bisexual flowers; there is only one kind of monoclinous species. Same as homoecioius. Compare with dicliny.
Monocotyledon (monocot)	One of the two classes of angiosperms usually characterized by having one cotyledon, parallel-veined leaves, and flower parts most often in threes. In the classification of Cronquist (1981), this class is called Liliopsida. In the APG classification it is not a monophyletic group. Palms and grasses are examples of economically important monnocots.
Monoecy (monoecious)	Referring to the sexual condition of a species of plant that bears male (staminate) and (female) pistillate flowers on the same plant. This is also an example of one of the two kinds of monoclinous species. Compare with dioecious.
Monograph	A scientific publication that includes all information known about a group of plants throughout its geographic range; e.g., Flora Neotropica Monographs.
Monophyletic	A group derived from the same ancestral taxon.
Monopodial	Referring to plants with indeterminate growth along one axis. Monopodial stems and branches appear straight.
Monosymmetric flower	A flower capable of being divided into only two equal parts (mirror images) by a line passing through the middle of a flower, i.e., other lines passing the middle of the flower will not give mirror images of one another; same as zygomorphic, bilaterally symmetrical, and irregular flowers and opposite of actinomorphic, monosymmetric, radially symmetrical, and regular flowers. This term can refer to other plant parts as well.
Morichal	A Spanish name referring to a palm swamp dominated by moriche palms Mauritia flexuosa. Same as aguajal also in Spanish and burital in Portuguese.
Moss life cycle	Alternation of generations of a moss . The conspicuous, green, represents the gametophyte generation which is everything between the spore and the embryo in this illustration whereas the sporophyte is consists of the stalk and capsule elevated above the green gametophyte generation.
Mucilage	A sticky, viscous liquid; e.g., that present among the leaf bases of Rapateaceae or in canals penetrating the ovary and sepals of some Lecythidaceae.
Mucilage ducts (= mucilaginous ducts)	Longitudinally oriented ducts that penetrate the ovary and sepals of some species of Lecythis. These ducts produce a mucilage that is hypothesized as a way to protect the fruits from predation, i.e., insects and other animals get their mouth parts gummed up if they try to penetrate the fruit wall.
Mucro (mucronate)	A sharp point at the apex of a leaf or a similar structure, e.g., a bract.
Muellerian bodies (also spelled Müllerian bodies)	Glycogen-rich food bodies located on fuzzy pads (trichilia) at the base of the petiole of some species of Cecropia (Cecropiaceae). Compare with pearl bodies.
Multiple big bang phenology	A flowering strategy in which abundant flowers are produced each day for a few days at several different times of the year.
Multiple fruit	A fruit formed from the ovaries of more than one flower, e.g., the pineapple fruit which consists of the fusion of the ovaries of the flowers of an inflorescence as the fruits develop.
Mutualism	A symbiotic relationship between two organisms that benefits both; examples are the relationship of Azteca ants with species of Cecropia (the ants receive food and shelter and the plant is protected from preditors by the ants) and the relationship between mycorrhizal fungi and plants (the fungus receives carbohydrates and the plant receives nutrients).
Mycelium (plural = mycelia)	The totality of hyphae that comprise the above and below ground parts of a fungus.
Mycoheterotroph (adj.= mycoheterotrophic)	Unable to synthesize organic compounds from inorganic substrates, i.e., this kind of plant does not photosynethesize and is not green in color because it lacks chlorophyll. It is called a mycoheterotroph because it receives photosynthate from other plants through fungal ( = mycorrhizal) connections.
Mycoheterotroph (mycoheterotrophic)	A heterotrophic plant that is without chlorophyll, lives on decayed plant material, and depends on a symbiotic relationship with a fungus to obtain food.
Mycorrhiza (plural = mycorrhizae)	A mutualistic symbiotic relationship between certain fungi and the roots of many species of vascular plants. Both the fungus and the vascular plant benefit---the fungus receives carbohydrates from the plant and the plant receives receives mineral nutrients from the fungus. In order to facilitate the transfer of carbohydrate and minerals the hyphae of the fungus penetrate the roots of the vascular plant hosts.
Myrcioid embryo	A type of embryo found in the Myrtaceae in which the cotyledons are normally thin, leafy, and folded, and the narrow, cylindrical hypocotyl is about the same length as the cotyledons and encircling them. Compare with eugenioid embryo and myrtoid embryo.

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