New Entities ofPaspalumand a Synopsis of the Dilatata Group

Abstract

Abstract—New entities in the allopolyploid Dilatata complex ofPaspalumare formally described and illustrated. Three sexual tetraploids formerly subsumed underPaspalum dilatatumare recognized as discrete taxonomic entities:P. plurinerveandP. vacarianumare described as new species, andP. dilatatumsubsp.flavescensis upgraded to species rank asP. flavescens.BothP. vacarianumandP. plurinerveare distributed in the Brazilian southern Plateau (Planalto Meridional), in the states of Rio Grande do Sul and Santa Catarina, the first one in the eastern region and the second one in the western region including adjacent areas of NE Argentina.Paspalum flavescensis distributed in southeastern Uruguay and the provinces of Buenos Aires and Córdoba (Argentina). The apomictic allohexaploidP. torrense, distributed along the coastal areas of the Brazilian states of Rio Grande do Sul, Santa Catarina, and Paraná, and adjacent regions along the edge of the southern Plateau, also deserves specific status, whereas two further hexaploid biotypes are differentiated from the pentaploidP. dilatatumvar.dilatatumand described asPaspalum dilatatumvar.chiruandP. dilatatumvar.uruguaianense.Paspalum dilatatumvar.chiruis restricted to a small area around the locality of Molles Grande, in the department of Paysandú, Uruguay; whereasP. dilatatumvar.uruguaianenseis distributed in the SW of Rio Grande do Sul, Brazil, and northern Uruguay. The Dilatata group ofPaspalumis thus comprised of 8 species and 3 varieties, which are summarized here and for which an identification key is provided.