A new variety of Senna birostris (Leguminosae, Caesalpinioideae) from Argentina

Senna birostris previously included seven varieties distributed mostly above 2000 m, in the Andes, between the equator and 33°S. According to Irwin & Barneby,Senna birostris var.hookeriana was the only variety in Argentina, distributed from the Jujuy province to the San Luis province. New observations led us to identify two distinct entities that have gone under this taxon. The new variety,Senna birostris var.jallaguensis, is described from Argentina and illustrated herein and is compared toSenna birostris var.hookeriana s.str.