Fabaceae
Herbs, trees, shrubs or climbers. Lvs usually alternate, simple or variously compound, often 3-foliolate, 1-imparipinnate, 1-paripinnate, or 2-pinnate, sometimes tendrilous, reduced to spines, scales or phyllodes, or even 0, usually stipulate. Fls in racemes, spikes, fascicles, heads or solitary, either regular and then often unisexual, or zygomorphic and then usually ⚥. Calyx usually 5-merous, regular or asymmetric with teeth variously reduced and united, imbricate or valvate in bud. Petals usually 5. Stamens mostly 10, numerous in Mimosoideae, free or united into a tube, often with one stamen remaining free and the tube split; anthers 1-2-locular. Ovary usually 1-locular, rarely transversely septate; style usually long with terminal stigma; ovules in 2 rows but appearing in 1 rank, anatropous or amphitropous, ascending or pendent. Fr. typically a pod dehiscing by both sutures, but sometimes by one suture or indehiscent, usually dry or sometimes fleshy, straight, curved or spirally coiled, sometimes lomentaceous; seeds often strophiolate.
SYNOPSIS
The family is divided into 3 subfamilies; these are treated as separate families by some authorities. The 3 subfamilies are broadly distinguished as follows; they are then treated separately.
- A. Subfam. CAESALPINIOIDEAE.
- Lvs usually 1-2-pinnate, rarely simple. Calyx and petals imbricate in bud. Stamens 10 (in N.Z. spp.); fls ± zygomorphic; petals distinct.
- B. Subfam. FABIOIDEAE.
- Lvs 1-pinnate, digitate, 3-foliolate, simple or 0. Calyx and petals imbricate in bud. Stamens 10 (in N.Z. spp.); fls zygomorphic and typically having a large posterior standard, 2 lateral wings enclosing (at least partly) 2 coherent petals forming the keel. The keel usually enclosing the stamens and style.
- C. Subfam. MIMOSOIDEAE.
- Lvs 2-pinnate or reduced to phyllodes. Calyx and petals valvate in bud. Stamens numerous (in N.Z. spp.); fls regular; petals indistinct.
c. 650 genera, 18000 spp., cosmopolitan.
The family is often known by the alternative family name Leguminosae. It is one of the largest families of flowering plants and the legumes are of major importance in both agriculture and horticulture. Their ability to fix atmospheric nitrogen, by way of Rhizobium bacteria associated with the roots, makes many legumes valuable as crops in areas with poor soils, but also makes many spp. aggressive weeds.
