Roystonea Regia - Taxonomy

Taxonomy

Roystonea is placed in the subfamily Arecoideae and the tribe Roystoneae. The placement Roystonea within the Arecoideae is uncertain; a phylogeny based on plastid DNA failed to resolve the position of the genus within the Arecoideae. As of 2008, there appear to be no molecular phylogenetic studies of Roystonea and the relationship between R. regia and the rest of the genus is uncertain.

The species was first described by American naturalist William Bartram in 1791 as Palma elata based on trees growing in central Florida. In 1816 German botanist Carl Sigismund Kunth described the species Oreodoxa regia based on collections made by Alexander von Humboldt and Aimé Bonpland in Cuba. In 1825 German botanist Curt Polycarp Joachim Sprengel moved it to the genus Oenocarpus and renamed it O. regius.

The genus Oreodoxa was proposed by German botanist Carl Ludwig Willdenow in 1807 and applied by him to two species, O. acuminata (now known as Prestoea acuminata) and O. praemorsa (now Wettinia praemorsa). Although these species were transferred to other genera, the genus Oreodoxa continued to be applied to a variety of superficially similar species which were not, in fact, closely related. To address this problem, American botanist Orator F. Cook created the genus Roystonea, which he named in honour of American general Roy Stone, and renamed Kunth's species Roystonea regia.

Cook considered Floridian populations to be distinct from both the Cuba R. regia and the Puerto Rican R. borinquena, and he placed them in a new species, R. floridana, which is now considered a synonym of R. regia. In 1906 Charles Henry Wright described two new species based on collections from Georgetown, British Guiana (now Guyana) which he placed in the genus Euterpe — E. jenmanii and E. ventricosa. Both species are now considered synonyms of R. regia. The name R. regia var. hondurensis was applied by Paul H. Allen to Central American populations of the species. However, Scott Zona determined that they did not differ enough from Cuban populations to be considered a separate variety.

Based on the rules of botanical nomenclature, the oldest properly published name for a species has priority over newer names. Bartram applied the Linnaean binomial Palma elata to a "large, solitary palm with an ashen white trunk topped by a green leaf sheath and pinnate leaves" growing in central Florida. While no type collection is known, there are no other native palms that would fit Bartram's description. In 1946 Francis Harper pointed out that Bartram's name was valid and proposed a new combination, Roystonea elata. Liberty Hyde Bailey's use of the name in his 1949 revision of the genus, established its usage.

Harper's new combination immediately supplanted Cook's R. floridana, but there was disagreement as to whether Cuban and Floridian populations represented a single species or two species. Zona's revision of the genus concluded that they both belonged to the same species. According to the rules of botanical nomenclature, the correct name of the species should have been Roystonea elata. Zona pointed out, however, that the name R. regia (or Oreodoxa regia) has a history of use in horticulture that dated from at least 1838, and that the species had been propagated around the world under that name. Roystonea elata, on the other hand, had only been used since 1949, and was used much less widely. On that basis, Zona proposed that the name Roystonea regia should be conserved.