The two excellent fodder grass species of genus Cenchrus - C.ciliaris (Cc) and C.setigerus (Cs) - are inhabitants of drier sandy areas throughout Africa, the Canary Islands, Madagascar and eastwards to India. In India, they mostly occur in western parts, including the Great Indian Desert. Small patches of the two grass species also occur in semi-arid tracts of southern India. In its area of distribution, the two species exhibit high degrees of morphological and physiological distinctions warranting population differences. Extensive surveys and intensive studies established 25 ecotypes of grass Cc and 9 of grass Cs in western India. The population differences lie in morphological, physiological and cytological aspects. Mathematical approach has confirmed the distinction. Biochemical analysis further supported the population differences. Culture experiments have established high forage yielding ecotypes. Extensive semi-natural grazing lands of the two species occur in the region. Forage yielding capacity varies between 250 and 750 g m2/y1. Herbage dynamics, system transfer functions and accumulation and flow rates give a good knowledge of energy flow in the semi-natural grazing lands dominated by the two species. Some of the ecotypes of the two grasses have high nutritive value in terms of total protein and digestability. Seed production, germinability and culture experiments have shown its establishment potentials. Accordingly, cultivation of some of the ecotypes of the two grass species in India, Australia, USA and Africa have given encouraging results.