Rogersonanthus

Primary tabs

Rogersonanthus

Description

Shrubs or trees. Leaves sessile or shortly petiolate, 19-143 mm long; 1-9-veined. Inflorescences terminal, a small dichasium; bracts and bracteoles scale-like. Flowers pedicillate, 5-merous, actinomorphic; calyx fused from base up to ca. 3/4 of length, coriaceous, campanulate, lobes elliptic, with a thickened dorsal and glandular area, apex obtuse; corolla bud apex rounded; corolla fused at base, coriaceous and fleshy, funnel-shaped to narrowly salver-shaped, 21-45 mm long; androecium zygomorphic with stamens and style bent towards bottom of corolla mouth; stamens inserted in lower half of corolla tube, of unequal length, base of filaments without appendages, anthers lanceolate, connective apex obtuse; pollen in tetrads; pistil with nectary disk around base, stigma bilamellate. Fruit a capsule, with persistent calyx and deciduous corolla; seeds angular, testa pattern with concave and convex cells and rimmed edges (unwinged).

Distribution

Guyana, Republic of: present Neotropics: present Trinidad: present tepuis in Venezuela and Guyana: present
2 species from the Neotropics, from tepuis in Venezuela and Guyana, and Trinidad; 1 species in Guyana.

Notes

Rogersonanthus was segregated from Macrocarpaea by Maguire & Boom (1989), based on the presence of pollen tetrads instead of pollen monads (Nilsson, 1968); the segregation is supported by phylogenetic analyses (Struwe et al., 2009). The species Rogersonanthus coccineus Steyerm. ex Struwe, S. Nilsson & V.A. Albert is excluded from this genus and included in Roraimaea Struwe, S. Nilsson & V.A. Albert (Struwe et al., 2008).