LAURACEAE

Weakley, Alan S., Kees, John C., Sorrie, Bruce A., Ward, Scott G., Poindexter, Derick B., Brock, Mason, Estes, L. Dwayne, Bridges, Edwin L., Orzell, Steve L., Levin, Geoffrey A., McClelland, R. Kevan Schoonover, Schmidt, Ryan J. & Namestnik, Scott A., 2023, Studies In The Vascular Flora Of The Southeastern United States. Ix, Journal of the Botanical Research Institute of Texas 17 (1), pp. 191-257 : 225-226

LAURACEAE

TAMALA : The three Southeastern United States native species of Persea are better treated in Tamala , as formerly done by C.S. Rafinesque and J.K. Small

Primary author:Alan S.Weakley

Rohwer (1993) stated that many of the genera in the Lauraceae were “in need of revision” or “badly in need of revision,” and many were noted as likely needing splitting or changes in circumscription.In the three decades since, molecular phylogenetic results have clarified the circumscription of some of the component genera in ways that affect species present as native or naturalized in the southeastern North United States. Trofimov et al. (2016) removed Damburneya Raf. from Nectandra Rottb. , resulting in the recognition of Damburneya coriacea (Swartz) Trofimov & Rohwer (formerly often placed in Nectandra or Ocotea Aubl. ) in the Flora of the Southeastern United States (Weakley & Southeastern Flora Team 2022a). Work by Huang et al. (2016) and Yank et al. (2022) have resulted in the resegregation of Camphora Fabr. from Cinnamomum Schaeff. , resulting in treatment of the non-native and invasive camphor tree as Camphora officinarum Nees , often in the past called Cinnamomum camphorum (L.) J. Presl. Future changes in circumscription are likely in Lindera Thunb. —“almost certainly polyphyletic” and “badly in need of revision” ( Rohwer 1993)—and Litsea —“comprising both anatomically and morphologically different groups, suggesting that the complex can be split into smaller entities” ( Rohwer 1993) – and reworking of the circumscription of these genera may result in our few southeastern United States species being placed in other genera (both Lindera and Litsea are typified on Chinese species which may or may not clade with ours).

Persea Mill. (as broadly interpreted) is represented in the southeastern United States by three native species and the non-native and widely cultivated avocado, Persea americana P. Mill. Molecular phylogenetic results of Xiao et al. (2022) show five clades in tribe Perseeae . Clade I consists of P. borbonia in a clade with Dehaasia Blume 1836 , Nothaphoebe Blume 1851 (including its type species), and species of Alseodaphne Nees 1831 (including its type species). Clade II consists of Persea americana (the type species of Persea ). Clade III consists of Alseodaphnopsis H.W. Li & J. Li 2017 . Clade IV includes Phoebe Nees 1836 and a single sampled species of Nothaphoebe (not its type). Clade V includes species of Alseodaphne and Alsodaphnopsis, not including the types of either genus. Clade VI consists of Machilus Nees 1831 .

For the Flora of the Southeastern United States, continuing to treat our native species of “ Persea ” in Persea is clearly wrong; they are not congeneric with Persea americana (the type of the genus) under any conceivable circumscription of the genus (lumping the currently-recognized genera in all 6 clades into a single genus would not be credible). While it is conceivable that the components of Clade I could be treated as a single genus, our native Persea species (as represented in the analysis by P. borbonia ) are “basal” to the rest of Clade I ( Dehaasia , Nothaphoebe , and Alseodaphne ), and estimated to diverge from that set of east Asian and southeast Asian genera ca. 39 million years ago. Morphologically distinctive and phylogenetically and geographically isolated, our native “ Persea ” are best treated as a small genus endemic to the southeastern United States and the Bahamas. Fortunately, a genus name is already available: Tamala Raf. , named by C.S. Rafinesque (1838), and apparently based on Laurus borbonia L, judging from his reference to L. borbonia in his description of Tamala . Regarding the etymology of the generic name, Rafinesque merely mentioned “(n. ind).” Although one might interpret that abbreviation as indicating that Rafinesque derived the genus name from a native American language ( tamala = thunderbolt), it appears that he instead derived it from Sanskrit of India ( tamala = dark blue, alluding to Laurus tamala Buch.-Ham. ). It is additionally helpful that Tamala has a half century of familiarity in the southeastern United States, because of its use in Small’s influential floras ( Small 1903, 1913, 1933). We therefore recognize Tamala borbonia (L.) Raf., T. humilis (Nash) Small , and T. palustris Raf. for the Flora of the Southeastern United States.