A NEW SPECIES OF SORGHASTRUM (POACEAE) FROM ISLA-SOCORRO, COLIMA, MEXICO

A new species of Sorghastrum, S, pohlianum, from Mexico is described a nd illustrated. A numerical analysis comparing the new species to the closest species (S. nutans and S. nudipes) was undertaken. The first t hree principal components explain 84% of the variation of the taxa inv olved. In addition there is morphological evidence to distinguish the new species from its closest relatives. It differs from S. nutans by s howing smaller inflorescences, having sterile lemmas and anthers, and having somewhat smaller but wider blades and different flowering perio ds. In addition, it is distinguished from S. nudipes due to the presen ce of auricles >1 mm long and inflorescence branches bearing spikelets along their entire length.