UBCBG accessions of Rhamnus purshiana are being relabelled as Frangula purshiana. This change is based on Generic limits in Rhamnus L. s.l. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies by K. Bolmgren and B. Oxelman published in Taxon, Volume 53, Number 2, 1 May 2004 , pp. 383-1(-381)
Frangula has been moved in and out of Rhamnus like a yo-yo over the last 240 years . . . I wonder if this will really be the last move?? Presume you're doing the same for Frangula californica and any others in this (sub)genus you have?
The only other Rhamnus species listed in the garden's database is Rhamnus alnifolia. I am not quite sure about the placement of that species. It was not mentioned in the article and seems to remain in the genus Rhamnus according to GRIN and others. http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?10359
