Two New Species of the Genus Sterigmapetalum (Rhizophoraceae) from the Venezuelan and Brazilian Amazonian Region

Abstract

Two new species of Sterigmapetalum subg. Sterigmapetalum are described from Vene- zuela and Brazil: S. chrysophyllum and S. plum- beum. Relationships with related species are dis- cussed, and an illustration for each species is provided. RESUMEN. Se describen dos nuevas especies de Sterigmapetalum subg~nero Sterigmapetalum de Venezuela y Brasil: S. chrysophyllum y S. plum- beum. Se discuten sus relaciones con las especies afines y se presentan ilustraciones de cada una de ellas. Sterigmapetalum Kuhlmann is a small neotropi- cal genus with nine species in the Rhizophoraceae. Sterigmapetalum and Cassipourea Aublet were seg- regated by Steyermark & Liesner (1983) into a new tribe, the Hypogyneae. Subsequently, Tobe & Ra- ven (1987), based on a detailed study of the mor- phology of the seed, flower, and fruit, placed these two genera in the Macarisieae, a treatment origi- nally employed by Schimper (1893) a century ear- lier. Eight of the nine species of Sterigmapetalum oc- cur in northern South America (Colombia, Vene- zuela, Guyana, and Surinam) and one (S. obovatum Kuhlmann) is restricted to the western and central Amazonian region of Peru and Brazil (Prance et al., 1975). Trees 15-20 m high; branches 3-verticillate, te- rete, covered completely by a yellow-ocher pubes- cence when young, glabrous or sparsely adpressed- pubescent when mature. Stipules triangular, acuminate, 3-5 mm long, with yellow pubescent trichomes on both surfaces, internally glandular at the base. Leaves 3-whorled, the blades coriaceous, elliptical or oblong-elliptical, 3-8 x 1.5-5.5 cm, obtuse to truncated at the base, retuse at apex, mar-