Concept:Forage grasses are grasses used as animal feed, while legumes belong to a different plant family.Explanation:Pennisetum purpureum, Panicum maximum, and Axonopus compressus are all forage grasses.Calopogonium mucunoides is a legume, not a grass.Only one option does not belong to the grass group.Answer:D. Calopogonium mucunoides