Phylogenetics of Sporobolus and relatives (Poaceae, Chloridoideae)

COLUMBUS T.; DENHAM S. S.; INGRAM A.; LEHMAN K.; ZUNIGA J.; KIEL C.; CHHETRI H.; FISHER A.

Columbus

Congreso; Botany 2012 - The Next Generation; 2012

ASPT, IAPT

Sporobolus (Poaceae, Chloridoideae) is distributed worldwide, primarily in the tropics and subtropics, and includes nearly 200 species, many of which are halophytes.  Previous molecular phylogenetic research has demonstrated that several other genera are nested within Sporobolus, rendering it paraphyletic.  Among these genera is Spartina.  In order to improve our understanding of relationships, trait evolution, and historical biogeography in the Sporobolus clade, we expanded sampling appreciably to include most species from the Americas, Australia, and southern Africa, and employed several chloroplast and nuclear loci for phylogenetic estimation.  Noteworthy morphological shifts include a transition to a racemose inflorescence (primary branches only) in Spartina from paniculate, and from single to multiple florets per spikelet in a few species.  The geographical history of the clade is complex, but the earliest diverging clades are African, and a number of intercontinental dispersal events are inferred.