Leguminosae-Mimosoideae Kunth
Alternatively Mimosaceae R.Br.
~ Leguminosae
Habit and leaf form. Trees and shrubs (mainly), or herbs (rarely); resinous, or not resinous. ‘Normal’ plants, or switch-plants (commonly); phyllodineous (often), or with the principal photosynthesizing function transferred to stems. Leaves well developed (usually), or much reduced (not infrequently). The herbs annual, or biennial, or perennial; with neither basal nor terminal aggregations of leaves. Self supporting (mostly), or climbing; the climbers scrambling. Leptocaul. Helophytic, or mesophytic, or xerophytic. Heterophyllous (e.g. Acacias with bipinnate juvenile and phyllodineous mature foliage), or not heterophyllous. Leaves evergreen, or deciduous; small to very large; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy, or membranous, or modified into spines; petiolate, or subsessile, or sessile; non-sheathing; gland-dotted, or not gland-dotted; without marked odour; edgewise to the stem, or with ‘normal’ orientation; simple (as phyllodes), or compound; pulvinate (usually), or epulvinate; when compound, bifoliolate, or ternate (?), or pinnate, or bipinnate (usually). Leaflets pulvinate, or epulvinate. Lamina one-veined, or pinnately veined, or parallel-veined. Leaves stipulate (usually), or exstipulate (or inconspicuous). Stipules intrapetiolar; scaly, or leafy, or spiny, or represented by glands; caducous, or persistent. Leaves without a persistent basal meristem.
Leaf anatomy. Extra-floral nectaries present (commonly, on rachides), or absent (?). Mucilaginous epidermis present, or absent. Stomata anomocytic, or paracytic, or anisocytic, or tetracytic, or cyclocytic.
Lamina dorsiventral, or isobilateral, or centric; with secretory cavities, or without secretory cavities. Secretory cavities containing oil, or containing mucilage, or containing resin. The mesophyll containing mucilage cells, or not containing mucilage cells. Minor leaf veins with phloem transfer cells (e.g. species of Mimosa, Neptunia), or without phloem transfer cells (e.g. Acacia, Albizzia, Adenenanthera, Dichrostachys, Enterolobium, Leucaena, Pithecellobium, Prosopis and Wallaceodendron).
Stem anatomy. Secretory cavities present, or absent. Cork cambium present (usually), or absent; initially deep-seated, or superficial. Nodes tri-lacunar, or penta-lacunar. Primary vascular tissue in a cylinder, without separate bundles, or comprising a ring of bundles. Cortical bundles present, or absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified (?). ‘Included’ phloem present, or absent (?). Xylem with vessels. Vessel end-walls simple. Vessels with vestured pits, or without vestured pits (?). Wood storied, or partially storied (VPI); parenchyma apotracheal, or paratracheal (?). Sieve-tube plastids P-type (12 genera); type IV (subtype (a) in 12 genera).
Reproductive type, pollination. Plants hermaphrodite (mostly), or monoecious, or andromonoecious, or polygamomonoecious. Anemophilous, or entomophilous, or ornithophilous, or cheiropterophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in heads. The terminal inflorescence unit racemose. Inflorescences terminal, or axillary; pseudanthial, or not pseudanthial. Flowers minute, or small; regular (mainly), or somewhat irregular (sometimes, in the Parkieae); neither papilionaceous nor pseudo-papilionaceous; (3–)5(–6) merous; cyclic, or partially acyclic (?). Sometimes the androecium acyclic (?). Flowers tetracyclic, or pentacyclic to polycyclic. Floral receptacle developing a gynophore, or with neither androphore nor gynophore. Free hypanthium present (e.g. Dinizia), or absent.
Perianth with distinct calyx and corolla; 6–12; 2 whorled; isomerous. Calyx (3–)5(–6); 1 whorled; gamosepalous (usually), or polysepalous; lobulate, or blunt-lobed, or toothed; regular; valvate (mostly), or imbricate (Parkieae); with the median member anterior. Corolla (3–)5(–6); 1 whorled; polypetalous, or gamopetalous; nearly always valvate (imbricate only in Dinizia); regular; white, or yellow, or orange, or red, or pink, or purple, or blue (?).
Androecium (3–)5(–12), or 12–100 (to ‘many’). Androecial members free of the perianth, or adnate (to the corolla); all equal, or markedly unequal; free of one another, or coherent; often 1 adelphous; 1 whorled, or 2–6 whorled. Androecium exclusively of fertile stamens (usually, except in sterile flowers), or including staminodes (e.g. Pentaclethra). Stamens (3–)5(–12), or 12–100 (to ‘many’); isomerous with the perianth to polystemonous; filantherous. Anthers separate from one another, or connivent; dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged, or unappendaged. The anther appendages when present apical (in the form of a deciduous gland). Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. Anther wall initially with one middle layer, or initially with more than one middle layer (?); of the ‘dicot’ type. Tapetum usually glandular. Pollen shed in aggregates (often), or shed as single grains; when aggregated, in tetrads, or in polyads. Pollen grains aperturate (usually), or nonaperturate (?); (2–)3(–4) aperturate, or 6 aperturate (?); colporate (commonly), or porate, or rugate (?); 2-celled (mostly), or 3-celled (sometimes, in Calliandra).
Gynoecium 1 carpelled (usually), or 2–16 carpelled (Archidendron (Australia, New Guinea), Affonsea and Klugiodendron (South America)); partly petaloid (the style of Petalostylis with three petaloid lobes), or non-petaloid. Carpels reduced in number relative to the perianth (mostly), or isomerous with the perianth to increased in number relative to the perianth (rarely). The pistil 1 celled. Gynoecium monomerous (nearly always), or apocarpous (rarely); of one carpel (nearly always), or eu-apocarpous; superior. Carpel apically stigmatic; 2–100 ovuled (i.e. to ‘many’, usually in alternating rows along the placenta). Placentation marginal (along the ventral suture). Gynoecium median (the placenta posterior, on the ventral suture). Ovary sessile to stipitate. Ovules pendulous to ascending (?); biseriate; arillate, or non-arillate; anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle, or not contributing to the micropyle (?). Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral (rarely), or persistent (mostly). Synergids hooked (often with filiform apparatus). Endosperm formation nuclear. Endosperm haustoria present; chalazal, or lateral (rarely). Embryogeny onagrad, or asterad, or caryophyllad (?).
Fruit non-fleshy (mostly), or fleshy. The fruiting carpel dehiscent, or indehiscent; a legume (usually), or a follicle, or samaroid, or a loment. Fruit elastically dehiscent, or passively dehiscent (?). Dispersal unit the seed, or the fruit. Seeds thinly endospermic, or non-endospermic; small to medium sized; winged, or wingless. Seeds with starch, or without starch (?). Seeds without amyloid. Cotyledons 2; usually flat. Embryo chlorophyllous; usually straight (the radicle straight). Micropyle zigzag, or not zigzag (?).
Seedling. Germination phanerocotylar (mostly), or cryptocotylar.
Physiology, biochemistry. Nitrogen-fixing root nodules present (very commonly), or absent (?). Not cyanogenic. Alkaloids present (commonly), or absent. Iridoids not detected. Proanthocyanidins present, or absent (?); when present, cyanidin, or delphinidin, or cyanidin and delphinidin. Flavonols present (mostly), or absent (?); kaempferol and quercetin, or quercetin and myricetin, or kaempferol, quercetin, and myricetin (?). Ellagic acid consistently absent. Arbutin present, or absent (?). Aluminium accumulation not found. Sugars transported as sucrose (in the 5 genera sampled). C3.
Geography, cytology. Tropical, subtropical and warm temperate.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Fabiflorae; Fabales. Cronquist’s Subclass Rosidae; Fabales. APG (1998) Eudicot; core Eudicot; Rosid; Eurosid I; Fabales. Species about 3200. Genera about 60; Abarema, Acacia, Albizia, Adenanthera, Adenopodia, Affonsea, Albizia, Amblygonocarpus, Adenanthera, Archidendron, Archidendropsis, Aubrevillea, Calliandra, Calliandropsis, Calpocalyx, Cedrelinga, Cojoba, Cylicodiscus, Desmanthus, Dichrostachys, Elephantorrhiza, Entada, Enterolobium, Faidherbia, Fillaeopsis, Gagnebina, Goldmania, Havardia, Indopiptadenia, Lemurodendron, Leucaena, Lysiloma, Marmaroxylon, Mimosa, Mimozyganthus, Neptunia, Newtonia, Parapiptadenia, Pararchidendron, Paraserianthes, Parkia, Pentaclethra, Piptadenia, Piptadeniastrum, Piptadeniopsis, Pithecellobium, Plathymenia, Prosopidastrum, Prosopis, Pseudoentada, Pseudopiptadenia, Pseudoprosopis, Schleinitzia, Serianthes, Stryphnodendron, Tetrapleura, Wallaceodendron, Xerocladia, Xylia, Zapoteca, Zygia.
This temporary description reflects incomplete breakdown of esoteric characters across the subfamilies of Leguminosae sensu lato (q.v.). However, it is clear that the many features which tend to distinguish the subfamilies all involve rather numerous exceptions, are very incompletely documented, or are not universally applicable.
Illustrations. • Technical details (Acacia, Albizzia, Mimosa).
Cite this publication as: ‘L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://biodiversity.uno.edu/delta/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).
