Parryella rotundata Wooton, Bull. Torrey Bot.

Parryella rotundata Wooton, Bull. Torrey Bot. View in CoL Club 25(8): 457 (1898).

Homotypic synonym= Errazurizia rotundata (Wooton) Barneby.

This transference adds a second species to Parryella , until now conformed by P. filifolia , and reduces from four to three the number of species of Errazurizia , namely E. benthamii , E. megacarpa and E. multifoliolata (Clos) I.M.Johnst.

3. Psorothamnus is paraphyletic, with species falling into two non-sister clades. One of the Psorothamnus subclades, including the type species of the genus ( P. emoryi ), results sister to Dalea + Marina , a result that receives the highest (100 %) bootstrap value in the partitioned ITS and the matK/trnK analyses, and the combined ITS + matK/trnK dataset. Altogether, this trigeneric assemblage is recovered as sister to a second Psorothamnus subclade with P. arborescens , P. fremontii , P. kingii , P. schottii , and P. spinosus . The bootstrap values that support the latter subcla- de range from 99 % in the ITS-based analysis to 100 % in the matK/trnK and the combined ITS + matK/ trnK analysis. All these species are former members of Psorodendron , a genus described as such in 1919 based on the type species P. johnsonii (= P. fremontii ), making imperative its reinstatement. The genus Psorodendron was proposed originally by Rydberg (1919) as distinct from Psorothamnus based on the presence of pedicellate flowers and exserted pods in the former, versus sessile flowers and inserted pods in the latter. An updated description of the genus is here provided, based on all the species assigned to it, and described by Rydberg (1919, 1928a, 1928b), and Barneby (1977, under Psorothamnus sect. Capnodendron Barneby, P. sect. Xylodalea (S. Wats.) Barneby , and P. sect. Winnemucca Barneby ).