The species of the genus Deyeuxia (Poaceae, Pooideae) from Argentina and nomenclatural notes

Abstract

This first revision of the genus Deyeuxia in Argentina revealed 58 native taxa from America, threeof them endemic to Argentina, and the remaining ones also growing in Bolivia, Brasil and Chile. Three new taxa are described for science: Deyeuxia alba subsp. breviaristata (Argentina, Brasil andUruguay); Deyeuxia heterophylla var. puberilemma (Perú); Deyeuxia trichodonta var. hirsuta from (Argentina: Salta). The following taxa are new records for Argentina, Bolivia, Chile and Ecuador: Deyeuxia brevifolia var. brevifolia and Deyeuxia brevifolia var. expansa (Chile); Deyeuxia cabreraevar. cabrerae, D. cabrerae var. aristulata (Chile); D. cabrerae var. trichopoda (Chile); Deyeuxia curta (Ecuador); D. diemii (Chile); Deyeuxia filifolia (Chile); Deyeuxia hackelii (Chile); Deyeuxia minima (Argentina and Ecuador); Deyeuxia sclerantha (Ecuador); Deyeuxia spicigera var. spicigera Chile); Deyeuxia spicigera var. cephalotes (Argentina) and Deyeuxia trichodonta var. trichodonta (Bolivia).The new name Deyeuxia nana, for Agrostis caespitosa, and the following new combinations are established: Deyeuxia reitzii, Deyeuxia rupestris f. pilosa, Deyeuxia rupestris var. minor, D. tarmensis var. macrochaeta, and Deyeuxia velutina var. nardifolia. New synonyms are established for Deyeuxia heterophylla (Calamagrostis mulleri, Calamagrostis macbridei); Deyeuxia rupestris f. pilosa (Calamagrostis leonardii, Calamagrostis longearistata f. pilosa) and Calamagrostis epigeios (Calamagrostis chilensis). This revision includes a critical evaluation of morphological characters (some of them studiedby SEM) with taxonomic value at the generic and species level, and relationships among Deyeuxia and its closest genera are discussed. Nomenclatural considerations about problematic taxa, keys to Deyeuxia and related genera, and also to the species and subspecific taxa, descriptions, synonyms, illustrations, geographical distribution, ecological observations and vernacular names for everyspecies are presented in detail.