Rhoogeton

Etymology: From the Greek ροος, rhoos = stream, and γειτων, geitōn = neighbor, as the plants usually grow along streams.

Synonyms: -

Infrafamilial position: Gesnerioid Gesneriaceae (Gesnerioideae) - Episcieae (?).

Description: Terrestrial stemless plants with a small tuber, tuber with fibrous roots. Leaves one or few, petiolate, lamina rounded to oblong-ovate, penninerved. Cymes long pedunculate, several-flowered, condensed. Sepals free to base. Corolla tubular to trumpet-shaped, oblique in the calyx, tube with a dorsal sac or blunt spur at the base, limb with spreading lobes. Stamens 4, didynamous, included; filaments connate at base and inserted near corolla base; anthers coherent in pairs, dehiscing by longitudinal slits. Nectary a single dorsal emarginate gland. Ovary superior; stigma bilobed. Fruit a bivalved capsule, loculicidally dehiscent, valves opening to 180º.

Chromosome number: 2n = 18.

Species number: 4.

Type species: Rhoogeton cyclophyllus Leeuwenb.

Species names (incl. publication and synonyms): See Skog, L.E. & J.K. Boggan. 2005: World checklist of Gesneriaceae: http://persoon.si.edu/Gesneriaceae/Checklist.

Distribution: Guyana.

Notes: Despite the episcioid flowers, the species was regarded to be closely allied to Lembocarpus by Boggan (1991), sharing the tuber, stemless habit, similar inflorescences and position of ovules (only on outer side of placentae). Recent findings are controversial: morphological data and ndhF sequences place Rhoogeton in Episciceae, while ITS sequences imply its position outside of that tribe and possibly within Gloxinieae (Smith 2000). These data also do not suggest a closer relationship with Lembocarpus. Feuillet & Skog (2003) suggest a possible position in Episcieae.

Selected references: Feuillet & Steyermark, Fl. Venezuel. Guayana 5 (1999), reg. rev.; Feuillet & Skog, Brittonia 54: 352-361 (2003, “2002”), gen. inf.

Bibliography: See Skog, L.E. & J.K. Boggan. 2005. Bibliography of the Gesneriaceae. 2^nd edition: http://persoon.si.edu/Gesneriaceae/Bibliography.