Flora of Barro Colorado Island

Rhynchospora nervosa

(Vahl) Boeck. in Vid., Medd. Nat. For. Kjobenh.1869:43.1870.

Dichromena ciliataVahl; D. radicans sensu auct.

Junco menudo, Clavo

Weak herb, 10-70 cm tall. Leaves 10-45 cm long, 3-5 mm wide, glabrous or villous on upper surface. Bracts subtending inflorescence 4-6, unequal, 1-15 cm long, usually white near base on upper side; inflorescence a dense head held well above leaves; spikelets 3-15, nar­rowly ovoid, 5-10 mm long, the flowers bisexual; scales thin, brown to whitish, glabrous or rarely scabrid on keel and margin; stamens 3; style 2-cleft, exserted and white at anthesis. Achenes obovate, weakly flattened, white to brownish, with numerous transverse wrinkles, the style base brown or greenish, ± flattened. Croat 6808.

Common in clearings. May be found in flower and fruit throughout the year.

Svenson (1943) in the Flora of Panama reported this species to have black or brown achenes, but I have found them to be white or more rarely light brown at maturity. Achenes are exposed along the rachis as the bracts be­come deciduous, beginning at the base. Standley 40831, reported by Svenson as Dichromena pubera Vahl, should probably be included here despite the fact that the scales are scabrid on the keel and margins; its achenes are like those of R. nervosa, and it does not differ in any other way.

In Central America, flowers open between 9:00 and 11:00 A.M. and are visited by the bees Trigona sp., Fombus mexicanus, and Apis mellifera (Leppik,1955).

Throughout most tropical areas of the Western Hemi­sphere. In Panama, known principally from tropical moist forest in the Canal Zone, Bocas del Toro, Colón, Chiriqui, Veraguas, Panama, and Darién; known also from tropical dry forest in Los Santos, Herrera' Coclé, and Panama, from premontane dry forest in Los Santos, from premontane moist forest in the Canal Zone and Panama, from premontane wet forest in Chiriqui and Panama, and from tropical wet forest in Chiriqui.