Alternatively Fabaceae Lindl. (ambiguous)
Including Caesalpiniaceae R.Br., Cassiaceae Link, Hedysar(ac)eae J.G Agardh, Lathyraceae Burnett, Lotaceae Burnett, Mimosaceae R. Br., Papilionaceae Giseke, Phaseolaceae Ponce de Léon & Alvares, Robiniaceae(`-aceas') Welw., Swartzi(ac)eae Bartl.
Habit and leaf form. Trees, or shrubs, or herbs, or lianas; resinous, or not resinous. `Normal' plants, or switch-plants; the switch forms often with the principal photosynthesizing function transferred to stems, or phyllodineous. 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, or epiphytic, or climbing; the climbers stem twiners, or tendril climbers (via stem or leaf tendrils), or scrambling (then sometimes via hooks). Helophytic, or mesophytic, or xerophytic. Heterophyllous (e.g. Acacias with bipinnate juvenile and phyllodinous mature foliage), or not heterophyllous. Leaves evergreen, or deciduous; minute to very large; usually alternate; spiral, or distichous; `herbaceous', or leathery, or membranous, or modified into spines; petiolate to sessile; non-sheathing; gland-dotted, or not gland-dotted; edgewise to the stem (commonly when phyllodinous, especially in Australia), or with `normal' orientation; compound (commonly), or simple; pulvinate, or epulvinate; when compound,as is usual, unifoliolate, or ternate, or pinnate (commonly, either pari- or imparipinnate), or palmate, or bipinnate (commonly), or bifoliolate (e.g. Bauhinieae). Leaflets pulvinate, or epulvinate. Leaves nearly always stipulate. Stipules intrapetiolar; scaly, or leafy, or spiny; caducous, or persistent. Leaves without a persistent basal meristem.
Leaf anatomy. 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; with sclerencymatous idioblasts (occasionally), or without sclerenchymatous idioblasts. Minor leaf veins with phloem transfer cells (55 genera, including some from each subfamily), or without phloem transfer cells (67 genera. For taxonomic details on Caesalpinioideae and Papilionoideae, see Watson and Gunning 1981. For Mimosoideae, Pate and Gunning (cf. their 1969 summary) recorded as positive species of Mimosa, Neptunia and (dubiously) Calliandra; they recorded negatives for Acacia, Albizzia, Adenenanthera, Dicrosyachys, 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 absent, or developing from a conventional cambial ring, or anomalous; when anomalous, via concentric cambia (e.g. Koompassia, Derris, Mucuna, Wisteria). 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, or S-type; when P-type type IV.
Reproductive type, pollination. Hermaphrodite (in Caesalpinioideae and Papilionoideae), or monoecious, or andromonoecious, or polygamomonoecious.
Inflorescence, floral, fruit and seed morphology. Flowers usually aggregated in `inflorescences'; in panicles, in fascicles, in racemes, in spikes, and in heads. The terminal inflorescence unit usually racemose. Inflorescences terminal, or axillary; pseudanthial (e.g. Mimosoideae), or not pseudanthial. Flowers minute to large; regular (Mimosoideae), or somewhat irregular to very irregular (Papilionoideae, Caesalpinioideae). The floral asymmetry involving the perianth and involving the androecium. Flowers papilionaceous (Papilionoideae), or `pseudo-papilionaceous' (`ascending', in many Caesalpinioideae), or neither papilionaceous or pseudo-papilionaceous (regular in Mimosoideae); cyclic, or partially acyclic (Mimosoideae). In Mimosoideae, the androecium acyclic. Floral receptacle usually more or less cupular. Free hypanthium present, or absent.
Perianth with distinct calyx and corolla; (3-)5, or (6-)10(-11); 2 whorled; isomerous, or anisomerous. Calyx 5, or (3-)5(-6); 1 whorled; gamosepalous (below); bilabiate, or regular; imbricate, or valvate; with the odd member anterior. Corolla (1-)5; 1 whorled; polypetalous, or partially gamopetalous, or gamopetalous (in some Mimosoideae). Papilionoideae with 2 of the petals joined (the two ventral petals joined to form the `keel' of the `papilionate' corolla). The joined petals of the papilionate corolla anterior. Corolla imbricate (descending in Papilionoideae, ascending in Caesalpinioideae), or valvate (Mimosoideae), or with open aestivation (occasionally); white, or yellow, or orange, or red, or pink, or purple, or blue. Petals clawed, or sessile.
Androecium (1-)10, or 10-50 (often ten, but commonly fewer, especially in Caesalpinioideae, and sometimes `many' in Mimosoideae). Androecial members free of the perianth; all equal, or markedly unequal; free of one another (sometimes), or coherent (in a variety of configurations); when cohering 1 - adelphous, or 2 - adelphous (commonly with the tenth, posterior stamen free of the rest, whose filaments are united into a tube). Androecium exclusively of fertile stamens, or including staminodes. Stamens (1-)10(-50); reduced in number relative to the adjacent perianth, or isomerous with the perianth, or diplostemonous to polystemonous. Anthers dorsifixed; versatile; dehiscing via pores, or dehiscing via longitudinal slits; introrse; tetrasporangiate. 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 in Mimosoideae, infrequently elsewhere, e.g. Afzelia), or shed as single grains (usually); 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 colpate, or rugate; 2-celled, or 3-celled.
Gynoecium 1 (nearly always), or 2-16 (in a few Mimosoideae); monomerous (usually), or apocarpous; of one carpel (usually), or eu-apocarpous (rarely); 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). Ovules ascending; biseriate; arillate, or non-arillate; anatropous, or campylotropous to amphitropous, or hemianatropous; 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 (Papilionoideae, Mimosoideae), or persistent (most Caesalpinioideae). 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, or fleshy. The fruiting carpel dehiscent, or indehiscent; a legume (usually), or a follicle, or an achene, or samaroid, or a loment, or drupaceous. Fruit elastically dehiscent, or passively dehiscent. Dispersal unit the seed, or the fruit. Seeds commonly non-endospermic, or endospermic (then often scantily so); small to very large. Seeds with starch, or without starch. Seeds with amyloid, or without amyloid. Cotyledons 2. Embryo chlorophyllous (45/83 - representing all three subfamilies); straight, or curved. Micropyle zigzag, or not zigzag.
Seedling. Germination phanerocotylar, or cryptocotylar.
Nitrogen-fixing root nodules present (very commonly), or absent (unusual in Caesalpinioideae?). Physiology, biochemistry. Cyanogenic (rarely), or not cyanogenic (mostly). Cynogenic constituents tyrosine-derived, or phenylalanine-derived, or of Hegnauer's `Group C', or leucine-derived. Alkaloids present (commonly), or absent. Iridoids absent. 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 (from 54 species and 41 genera, representing all three subfamilies). Arbutin present, or absent. Aluminium accumulation not found. Sugars transported as sucrose. C3. C3 recorded in Acacia, Alysicarpus, Amorpha, Arachis, Astragalus, Caragana, Cassia, Cercidium, Crotalaria, Dalea, Dolichos, Genista, Gleditsea, Glycine, Hoffmanseggia, Indigofera, Lespedeza, Lotus, Lupinus, Medicago, Mimosa, Olneya, Phaseolus, Pisum, Prosopis, Pueraria, Robinia, Sesbania, Spartium, Stylosanthes, Tephrosia, Trifolium, Vicia, Vigna. Anatomy non-C4 type (Acacia, Arachis, Astragalus, Cassia, Mimosa, Pithecellobium, Prosopis, Psophocarpus, Psoralea, Trigonella etc., and 160 genera of Caesalpinioideae and Swartzieae examined by L.W. - cf. Watson and Dallwitz 1983).
Geography, cytology. Holarctic, Paleotropical, Neotropical, Cape, Australian, and Antarctic. Frigid zone, temperate, sub-tropical, and tropical. Cosmopolitan.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Fabiflorae; Fabales. Cronquist's Subclass Rosidae; Fabales. Takhtajan's Subclass Rosidae; Rosanae; Fabales. Species 12000. Genera about 650; Albizia, Inga, Pithecellobium, Acacia, Mimosa, Prosopis, Piptadenia, Entada, Parkia, Caesalpinia, Parkinsonia, Delonix, Gleditsea, Haematoxylum, Sclerolobium, Melanoxylon, Bauhinia, Cercis, Cassia, Ceratonia, Colophospermum, Copaifera, Brachystegia, Tamarindus, Amherstia, Sophora, Baphia, Podalyria, Glycine, Phaseolus, Vigna, Crotalaria, Lupinus, Cytisus, Medicago, Trifolium, Lotus, Indigofera, Astragalus, Vicia, Lathyrus, Pisum, Arachis, Aeschynomene, etc.
Economic uses, etc. Economically very important for food, fodder, fibres, dyes, gums, resins, oils, and `green manure'; e.g. peas (Pisum), lentils (Lens), peanuts (Arachis), beans (Phaseolus, Vicia), cowpeas (Vigna), soybean (Glycine), clover (Trifolium), alfalfa (lucerne, Medicago), lupins (Lupinus), sweet clover (Melilotus). Numerous cultivated ornamentals, e.g. Bauhinia, Wisteria, Acacia, Cassia, Cytissus, Genista, Albizia, Lathyrus. Important tropical timbers from Acacia, Albizzia, Dalbergia, Robinia, Sophora, etc.
Illustrations. legum365.gif legum367.gif legum288.gif legum369.gif legum370.gif
Additional, to be intercalated. The twiners twining clockwise, or twining anticlockwise (in Phaseolus, Wisteria).
