Concept:Pasture legumes are leguminous plants grown for grazing, while grasses are not legumes.Explanation:A.Cynodon pletostachyus is a grass, not a legume.B.Stylosanthes gracilis is a pasture legume, commonly called stylo.C.Panicum maximum is a grass.D.Pennisetum purpureum is a grass.Therefore, only the plant in option B belongs to the legume family.Answer:B. Stylosanthes gracilis