Themeda is a genus of plants in the grass family native to Asia, Africa, Australia, and Papuasia. There are about 18 to 26 species, many of which are native to Southeast Asia.Species Themeda anathera (Nees ex Steud.) Hack. - Afghanistan, Himalayas, Tibet Themeda arguens (L.) Hack. - Christmas grass - Sri Lanka, Southeast Asia, Papuasia, northern Australia Themeda arundinacea (Roxb.) A.Camus - Indochina, southern China, Indian Subcontinent, Malaysia, Indonesia Themeda avenacea (F.