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The families of flowering plants

L. Watson and M.J. Dallwitz

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; without conspicuous 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; borne edgewise to the stem, or ‘normally orientated’; 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. Leaf development not ‘graminaceous’. Domatia never explicitly mentioned for the family.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial, or centric. Extra-floral nectaries present (commonly, on rachides), or absent (?). Mucilaginous epidermis present, or absent. Stomata anomocytic, or paracytic, or anisocytic, or tetracytic, or cyclocytic. Hairs of numerous kinds present (in the subfamily). Lamina 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).

Axial (stem, wood) anatomy. Secretory cavities present, or absent. Cork cambium present (usually), or absent; initially deep-seated, or initially superficial. Nodes tri-lacunar, or penta-lacunar. Primary vascular tissues in a cylinder, without separate bundles, or comprising a ring of bundles. Internal phloem absent. Cortical bundles present, or absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The vessel end-walls simple. The vessels with vestured pits, or without vestured pits (?). The axial xylem at least sometimes including septate fibres, or without septate fibres. The parenchyma apotracheal, or paratracheal (?). The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified (?). ‘Included’ phloem present, or absent (?). The wood storied, or partially storied (VPI).

Reproductive type, pollination. Plants hermaphrodite (mostly), or monoecious, or andromonoecious, or polygamomonoecious. Pollination 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 ultimate inflorescence units 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 (recorded in 15 genera), or 2-celled and 3-celled (both states recorded 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. Nitrogen-fixing root nodules present (very commonly), or absent (?).

Physiology, phytochemistry. C3. Sugars transported as sucrose (in the 5 genera sampled). Not cyanogenic. Alkaloids present (commonly), or absent. Arbutin present, 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. Aluminium accumulation not found. Sieve-tube plastids P-type (12 genera); type IV (subtype (a) in 12 genera).

Geography, cytology. Tropical, subtropical and warm temperate.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Fabiflorae; Fabales. Cronquist’s Subclass Rosidae; Fabales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order 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.

General remarks. 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. • Acacia alata: Bot. Reg. 396, 1819. • Acacia decurrens: Bot. Reg. 371, 1819. • Acacia gunnii: Hooker, Fl. Tasmaniae (1860). • Acacia longifolia: Bot. Reg. 362, 1819. • Acacia longissima: Bot. Reg. 680, 1822. • Acacia myrtifolia: Bot. Mag. 302 (1795). • Acacia myrtifolia: Bot. Mag. 302 (1795), text. • Acacia siculiformis (as stuartiana): Hooker, Fl. Tasmaniae (1860). • Acacia verticillata (as ovoidea): Hooker, Fl. Tasmaniae (1860). • Acacia vestita: Bot. Reg. 698, 1823. • Acacia spectabilis: Bot. Reg. 29 (46), 1843. • Acacia uncinata: Bot. Reg. 1332, 1830. • Calliandra harrisii: Bot. Reg. 1839, 41. • Faidherbia albida: as Acacia albida, Bot. Reg. 1317, 1830. • Mimosa uruguensis: Bot. Reg. 33, 1842. • Paraserianthes lophantha: Bot. Reg. 361, 1819. • Leaf hairs of Mimosoideae (5 Mimosa species: Solereder, 1908).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 13th March 2017.’.