Prior to 1892, the staghorn or velvet sumac, cultivated worldwide, was known by the name Rhus typhina L. (e.g., Gray 1890). However, Sudworth (1892) noted that R. typhina (Linnaeus 1756) and Datisca hirta L. (Linnaeus 1753), are conspecific. Since the rule of priority below the genus rank was strictly maintained until August 1981 in the Code [e.g., Leningrad Code Art. 14 (Stafleu et al. 1978); Sydney Code Art. 14 (Voss et al. 1983)], he transferred D. hirta to Rhus and made the new combination R. hirta (L.) Sudw. and cited R. typhina as a synonym. In spite of its priority, the usage of R. hirta was only occasional (e.g., Britton and Brown 1897; Britton 1901), whereas the usage of R. typhina continued until 1991 (e.g., Fernald 1950; Kartesz and Kartesz 1980; Radford et al. 1968; USDA, SCS 1982; Voss 1985), when Kartesz and Gandhi (1991) revived the usage of R. hirta. However, Reveal (1991) argued against the revival of R. hirta. He stated that “Rhus typhina is in current use in all modern agricultural, botanical and horticultural literature, including all of the world's recent floras, manuals and checklists where the plant occurs. It has been used without exception in all recent horticultural encyclopedias. To replace it with R. hirta will result in unnecessary nomenclatural confusion.” Nevertheless, R. hirta was used by Kartesz (1994), Kartesz and Meacham (1999), and also by the USDA-PLANTS database, during 1994–2000. In the above regard, Reveal (1995) proposed the rejection of Datisca hirta (Rhus hirta) and provided an excellent summary of past usage (quoted): “… With adoption of the Tokyo Code, it becomes possible to reject any name that causes nomenclatural instability. Accordingly, the basionym of this disruptive name, Datisca hirta, is proposed for rejection. Rhus hirta was used by a few authors from 1892 until 1916, but the name was largely ignored after 1906 under Art. 51.3 of the Vienna Rules which permitted rejection of names based on a monstrosity, as was Britton's lectotype of Datisca hirta. Rhus hirta remained rejected under Art. 71 of post-1935 Codes until that Article was deleted in 1975. Even then, the name was not taken up until its priority was noted in 1991 (by Kartesz and Gandhi).” Reveal's proposal was accepted, and the names Datisca hirta and Rhus hirta have been listed as rejected in the codes [e.g., Greuter et al. 2000 (St. Louis Code Appendix IV); Wiersema et al. 2015 (Melbourne Code Appendix IV)]. Therefore, since 2000 one must use Rhus typhina for staghorn sumac, not Datisca hirta or Rhus hirta. Accordingly, Gleason and Cronquist (2007), US National Plant Germplasm System: GRIN Taxonomy (2015) and USDA, NRCS (2015) list R. typhina as the accepted name. The preceding name is used in the Flora of North America's forthcoming volume 13 containing Anacardiaceae.
Gandhi, K. N. (2016). Staghorn Sumac: Rhus typhina or R. hirta (Anacardiaceae). Http://Dx.Doi.Org/10.3119/15-37, 118(974), 232–234. https://doi.org/10.3119/15-37