Taxonomic Revision of Paspalum Group Caespitosa (Poaceae, Panicoideae, Paspaleae)

Abstract

A taxonomic revision and nomenclatural update for Paspalum L., group Caespitosa are presented. The group Caespitosa consists of perennial species, usually rhizomatous, with culms simple, erect, inflorescences terminal, pauci-racemose, and spikelets mostly ellipsoid to ovoid or obovoid. It is distributed from the southern United States to northeastern Argentina, with several taxa concentrated in the Caribbean Islands. We recognize 13 species and three varieties (i.e., Paspalum acutifolium León, P. albidulum Henrard, P. bakeri Hack., P. blodgettii Chapm., P. caespitosum Flüggé, P. chacoense Parodi, P. divergens Döll, P. galapageium Chase var. galapageium, P. galapageium var. minoratum Chase, P. galapageium var. redundans (Chase) Delfini & Zuloaga, P. indecorum Mez, P. laxum Lam., P. ligulare Nees, P. molle Poir., and P. redondense Swallen), and designate lectotypes for three names. We propose a new synonym for P. ligulare and a new variety for P. galapageium, and provide updates on inferential lectotypifications (for seven names) and on inferential neotypification (for P. caespitosum var. longifolium). We then comment on four situations of uncertainty, and present new geographic analyses of the species. Illustrations, a key for the species, and additional comments on morphology of the group Caespitosa are also included.