FABACEAE (LEGUMINOSAE)

Herbs, shrubs, trees, climbers or decumbent; very often bearing root nodules harbouring Nitrogen-fixing bacteria. Leaves alternate or opposite, simple, pinnate or bipinnate, less often palmately compound or 3-foliate, very rarely 1-foliate; leaves, petioles and leaflets variously modified into phyllodes or tendrils; stipules and stipulules present or absent, sometimes stipules modified into spines. Inflorescences racemes, corymbs, spikes, heads, panicles or flowers solitary. Flowers bisexual, rarely unisexual, actinomorphic, +/- zygomorphic to strongly zygomorphic, pentamerous, hypogynous or perigynous. Sepals usually 5, rarely 3 or 6, free or connate into a tube, sometimes bilabiate, rarely reduced or obsolete. Petals usually 5, rarely 0 or 6, usually isomerous with sepals; in zygomorphic flowers, petals free and unequal, imbricate or valvate, or free and often differentiated into papilionaceous corolla: upper petal (Standard or Vexillum) largest and outermost, 2 lateral petals (Wings or Alae) +/- parallel with each and inner to vexillum, lower 2 innermost petals usually connate by their lower margin and forming a Keel or Carina; in actinomorphic flowers corolla slightly united with 5 equal lobes. Stamens mostly 10, sometimes fewer or numerous, free or connate by their filaments to form an open or closed sheath, diadelphous or monoadelphous; anthers bithecous, uniform or dimorphic, then alternately basifixed and dorsifixed dehiscing longitudinally or by pores. Pistil 1, always monocarpellary (very rarely 2 or more free carpels), ovary superior, unilocular, ovules 1-numerous, inserted on adaxial suture, placentation marginal; style simple with terminal stigma. Fruit a pod or legume, dehiscent by one or both sutures or indehiscent, sometimes winged or jointed and breaking up into 1-seeded segments. Seeds without or with very scanty endosperm.

About 650 genera and 18000 species

This large family is divided into 3 subfamilies, now given the rank of families by some taxonomists:

1. Subfamily: Faboideae or Papilionoideae
2. Subfamily: Caesalpinioideae
3. Subfamily: Mimosoideae

FABOIDEAE OR PAPILIONOIDEAE

Herbs, shrubs, climbers or trees; very often bearing root nodules that harbour N-fixing bacteria. Leaves alternate, simple, pinnately or palmately compound; stipules sometimes present. Inflorescence racemose paniculate, umbellate, capitate, spicate; sometimes flowers solitary. Flowers bisexual, zygomorphic, rarely subregular, usually 5-merous, perigynous. Calyx gamosepalous, truncate or more or less distinctly 5-lobed or 5-toothed, 2 upper lobes or teeth often connate and opposed to the 3 lower. Petals 5, free, papilionaceous: upper petal largest and outermost (Standard or Vexillum), 2 lateral petals (Wings or Alae) +/- parallel with each and inner to vexillum, lower 2 innermost petals usually connate by their lower margin and forming a Keel or Carina. Stamens 10, rarely fewer, free or fused, mostly the anterior/adaxial/vexillary stamen free or nearly so and the 9 united together into open or closed sheath; anthers uniform or dimorphic, basifixed or dorsifixed. Pistil 1, monocarpellary; ovary superior, usually unilocular, many to 1-ovules on the marginal placenta; style 1; stigma 1, simple. Fruit a pod (or legume), showing great variety of forms, dehiscent by 2 or 1 sutures or indehiscent or jointed and breaking up into 1-seeded parts. Seeds sometimes arillate, with or without endosperm.

480 genera and 12000 species