A Revision of Deschampsia, Avenella, and Vahlodea (Poaceae, Poeae, Airinae) in South America1

A revision of the species of Deschampsia P. Beauv., Avenella (Bluff & Fingerh.) Drejer, and Vahlodea Fr. (Poaceae, Poeae, Airinae) present in South America is given. Fifteen species of Deschampsia and two monospecific genera segregated from Deschampsia—Avenella and Vahlodea—are found in the Andes of Argentina and Chile south of 30°S, typically in humid or damp sites and wetlands. Isolated populations of the cosmopolitan D. cespitosa (L.) P. Beauv. are also found in Bolivia and highlands of southern Brazil. Keys to differentiate among the species of Deschampsia and the allied genera Avenella and Vahlodea are provided. A lectotype is designated for D. berteroana (Kunth) Trin.