Hidden in plain sight: Morphological and phylogenetic evidence for , a species distinct from (Poaceae, Chloridoideae).

Two varieties of have been recognized, the widespread var. and the more narrowly distributed var. The two varieties differ in inflorescence form even more than that seen between many other closely related species of . We therefore asked whether these taxa might be better regarded as distinct species. A total of 93 vouchers were studied by using morphometry (principal components analysis and statistical tests), leaf micromorphology, ancestral state reconstruction, and/or molecular ( and ) phylogenetic analyses. Except from the tree all results supported elevation of var. to the rank of species, thus the new combination (M.E. Jones) L.F. Cuellar & Columbus comb. nov. et stat. nov., is proposed. Chloroplast and combined chloroplast-nuclear molecular trees depicted var. as monophyletic (even in sympatric populations with var. ) and reveals phylogenetic structure within var. for which the presence of new undescribed varieties of (different from ) is addressed differs from in having fewer branches per inflorescence, a bigger branch with more spikelets, and a shorter branch extension. Scanning electron microscopy revealed the presence of papillae on leaves of as a clear synapomorphy. Growing mature plants of from seeds in a greenhouse revealed a strong cleistogamous nature for this species for which gene flow in sympatric populations with seems unlikely A taxonomic treatment and distribution map for identification of is provided.