Fabaceae subfamily Caesalpinioideae - Legume family

Trees or shrubs, less often climbers or herbs. Leaves usually 1-pinnate, less often simple or 2-pinnate. Inflorescences usually of spikes or panicles of racemes, rarely of spikes or capitate; racemes sometimes condensed to umbel-like fascicles. Flowers usually ± zygomorphic. Sepals usually free, sometimes ± connate. Petals imbricate in bud, usually with the dorsal within and overlapped by the lateral, free or sometimes connate below, usually 5, sometimes reduced to 1 or 0. Stamens usually 10 or fewer (rarely numerous), free or ± connate below. Pods various. Seeds generally without areoles.

Comment: Colophospermum, Baikiaea, Cryptosepalum, Isoberlinia, Julbernardia and Brachystegia all include widespread dominants in the Zambezian Domain. All are woody, mostly trees, or shrubs (Cryptosepalum, Copaifera), or geoxylic suffrutices (Cryptosepalum & Brachystegia). Nitrogen fixing rhizobial root symbiosis does not occur in the group. Four of the most widespread woodland dominants (Cryptosepalum, Isoberlinia, Julbernardia) and )Brachystegia) have ectomycorrhizal symbiosis; both VAM (vesicular arbuscular) and EM occur in Afzelia quanzensis.

Remarkable is how self dispersed trees, employing woody pods which scatter the seeds when the valves split apart and twist with explosive force, have dominated vast areas of nutrient poor soils in tropical Africa. There is no parallel in other tropical continents. The method of dispersal is associated with strong dominance and contiguous crowns, slow migration, and difficulty in crossing barriers. Trees using this method of dispersal are restricted to areas with a mean annual rainfall of more than 600-650 mm.

Nowadays combined with the subfamilies Papilionoideae and Mimosoideae into the large family FABACEAE or LEGUMINOSAE. However, as all three are extensive and distinctive groups, it is still preferred to deal with them in separate lists.

Worldwide: 153 genera and 2,175 species, mostly tropical.

Zambia: 29 genera and 93 taxa.