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The convoluted history of the name Lisianthus

Common name: 

Latin name and synonyms: Rogersonanthus Maguire & Boom (1989)

Etymology: Rogersonanthus was named after botanist and mycologist Clark Rogerson of The New York Botanical Garden, a colleague of Dr. Bassett Maguire, who described this plant.

Species:   Two species. (It used to be three; Rogersonanthus coccineus has been moved to Roraimaea.)

Distribution:   The Guyana Shield in northern South America, including the tepui mountains of Guyana and Venezuela, plus the island of Trinidad.

Habitat:  Cloud forests, mountain meadows, bogs, and grasslands at high elevation.

Characteristics: Shrubs to trees. Leaves leathery. Inflorescence small, terminal cyme, 1–12-flowered; bracts scale-like. Flowers 5-merous. Calyx campanulate, fused at base, thick and leathery. Corollas green to yellow, funnelshaped, thick, and leathery; Stamens inserted in lower half of corolla tube; anthers lanceolate, recurved after anthesis. Pollen in tetrads. Gynoecium with glandular disk; style long; stigma bilamellate. Fruit an elliptic, leathery capsule, dehiscing medially or apically, sometimes nodding. Seeds angular, not winged; testa cells concave with band-like thickenings (R. quelchii).

Evolution and related plants: Rogersonanthus belongs to tribe Helieae and is most likely closely related to other tetrad-bearing genera such as Chelonanthus, Calolisianthus, and Symbolanthus.  Previously two of the species were included in Macrocarpaea, another Helieae genus, but Macrocarpaea has mostly pollen spread as monads (single pollen grains).

Economic uses: None known. 

Notes: 

Accepted species (synonyms in parenthesis) and their distribution:

References and publications: 

Ewan, J. 1948a. A revision of Macrocarpaea, a neotropical genus of shrubby gentians. Contr. U. S. Natl. Herb. 29: 209-251.

Maguire, B. & B. M. Boom. 1989. Gentianaceae, part 3. Pp. 2-56. In: B. Maguire & collaborators, editors. The Botany of the Guayana Highland – Part XIII. Mem. New York Bot. Gard. 51.

Struwe, L., J. W. Kadereit, J. Klackenberg, S. Nilsson, M. Thiv, K. B. von Hagen, & V. A. Albert. 2002. Systematics, character evolution, and biogeography of Gentianaceae, including a new tribal and subtribal classification. Pp. 21-309. In: L. Struwe & V. A. Albert (eds.), Gentianaceae: Systematics and Natural History, Cambridge University Press, Cambridge

© Lena Struwe, 2004