Roystonea altissima

Roystonea altissima is a large palm which reaches heights of 20 metres (66 ft). Stems are grey-brown and range from 25.5–35 centimetres (10.0–13.8 in) in diameter. The upper portion of the stem is encircled by leaf sheaths, forming a green portion known as the crownshaft which is normally 1.4–1.6 m (4.6–5.2 ft) long. Individuals have about 15 leaves with 4-metre (13 ft) rachises; the leaves hang well horizontal. The 1.2 m (3.9 ft) inflorescences bear violet male and female flowers. Fruit are 11.4–15.3 millimetres (0.45–0.60 in) long and 7.2–10.4 mm (0.28–0.41 in) wide, and are black when ripe.^[2]

Roystonea is placed in the subfamily Arecoideae and the tribe Roystoneae.^[3] 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.^[4] As of 2008, there appear to be no molecular phylogenetic studies of Roystonea^[3] and the relationship between R. altissima and the rest of the genus is uncertain.

The species was first described by Scottish botanist Philip Miller as Palma altissima.^[5] The species was largely overlooked for the next 180 years until American botanist Liberty Hyde Bailey took a look at the royal palms as a whole. Apparently unaware of Miller's description, Bailey applied a new name, Roystonea jamaicana, to the species. In 1963 Harold E. Moore synonymised Bailey's species with Miller's and proposed a new combination, R. altissima.^[2]

Roystonea altissima is known as the "Jamaican cabbage tree", "Jamaican royal palm" or the "mountain cabbage palm".^[2]

Riffle, Robert L. and Craft, Paul (2003) An Encyclopedia of Cultivated Palms. Portland: Timber Press. ISBN 0-88192-558-6 / ISBN 978-0-88192-558-6 (Page 441-442)