A NEW NAME FOR A BRAZILIAN SENNA (LEGUMINOSAE: CAESALPINIOIDEAE)

Abstract

The name Senna australis Irwin & Barneby is superfluous. As originally published by Irwin and Barneby (1982: 235), this name was based on Cassia australis Vellozo, with the (then prevailing) assumption that Vellozo's Florae fluminensis was published in 1825. They overlooked an article by Carauta (1973) indicating that, although it was printed in 1825, Vellozo's work was not distributed until 1829, a view upheld by Stafleu and Cowan (1986: 698). However, during this four year period, another Cassia australis was published for an Australian taxon by Sims (1826: t. 2676) in August of 1826. In a treatment of Australian Cassia (sensu lato) by Symon (1966: 102), C. australis Sims was dismissed as a later homonym of C. australis Vellozo in favor of C. odorata Morris, which was published in September of 1826. If one chooses to treat the Australian Cassia in the manner of Symon, C. australis Sims cannot be considered a later homonym and must be adopted in lieu of C. odorata Morris, over which it has priority. According to the stricter definition of Cassia adopted by Irwin and Barneby (1982), this Australian taxon is actually a member of Senna section Psilorhegma (Barneby, in litt.). A barrier, namely Senna australis Irwin & Barneby, now exists to the transfer of Cassia australis Sims to Senna. No name for this taxon in Senna is proposed here, this decision being best left to those working on the Australian Cassiinae. The Brazilian C. australis Vellozo must now be considered the later homonym and is therefore illegitimate. This leaves Senna australis Irwin & Bameby without a legitimate basionym, thus its priority dates from 1982 rather than the previously supposed 1825. Furthermore, Senna australis must now be viewed as a nomen superfluum, since Cassia appendiculata Vogel was included in the synonymy, a name with priority that should have been adopted. Rupert Barneby graciously reviewed the evidence presented above and urged that I publish the following combination to correct this situation: