Ptilagrostis in North America and Its Relationship to Other Stipeae (Gramineae)

Abstract

Oryzopsis kingii is transferred to Ptilagrostis as P. kingii on the basis of its morphological, anatomical, ecological, and cytological similarity to other members of that genus. In addition, P. porteri is transferred to P. mongholica as P. mongholica subsp. porteri. Stipa stillmanii, whose inclusion in Ptilagrostis has also been suggested, is retained in Stipa s.l. Numerical analyses of morphological similarities among various supraspecific taxa of Stipeae support previous suggestions that the generic limits within the tribe, particularly as interpreted in North America, should be reevaluated.