Ecologie :

Coastal and inland grassland and woodland; waste places, old cultivations and around dwellings; 0-240(-1170) m alt. (E. Africa; 1000-1800 m in Ethiopia, possibly not native; var. retusa). - Grounwater savanna, 700 m, Imatong Mts, S Sudan. -etc... Variable in type of racemes, in indumentum of stems and calyx. Pantropical. The original distribution is now much obscured by widespread cultivation or introduction as a weed. Generally regarded as Asiatic, but may well be native to the coastal regions of E Africa and the Mascarene Isl. where 2 variants occur. Comprises 2 vars. - Var. tunguensis (Pires de Lima) Polhill (bas.: C. tunguensis Pires de Lima) seems to occur in more undisturbed places than var. retusa (which is not yet recorded from Somalia); [see more in the book] Widespread due to its use as fibre plant and, more recently, green manure. Grown as an ornamental in Florida and tropical America. Only occurrences of var. tunguensis in the E part of Africa mapped.