Monographs Details: Rhynchospora graminea Uittien
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Family:Cyperaceae
Description:Distribution and Ecology - Distribution. Rare in Venezuela, Guyana, Suriname, and northeastern Brazil including Goias and Federal District. VENEZUELA. Amazonas: Great Rapids of the Orinoco, crystalline layer at 1-1.5 km E of Hotel Amazonas, Puerto Ayacucho, 100-120 m alt, Maguire et al 36042 (NY). GUYANA. Kaieteur Plateau, Maguire & Fanshawe 23308 (NY), Mt. Roraima, stony slopes with sandy soil, Philipp Camp, 5200-6000 ft alt, Tate 290 (NY). SURINAME. Zanderij I, savannah near aerodome, Lanjouw & Lindeman 228 (NY, U); Zanderij II, Maguire & Stahel 23675 (NY). BRAZIL. Goiás: Cabecevias du Rio Gauca, Glaziou 22355 (K, NY, P), Cristalina, Heringer 10133 (NY, UB); Distrito Federal: between Brasília and Zona do Calcáreo, Pires et al 9425 (NY, UB).

Discussion:

Type. Lanjouw 339 (U, holotype; NY, isotype) from Zanderij I, savannah, Suriname.

Although Uittien assumed that R. graminea might perhaps be conspecific with R. spruceana, a well-developed form of R. tenuis, it is without doubt a distinct species.

It differs from R. tenuis in its coriaceous glumes, less wrinkled achenes, and very small dark-colored style-bases in contrast to the membranous glumes, strongly wrinkled achenes, and large pale style-bases in the latter. Habitually R. graminea has narrow inclined inflorescences with erect branches, while in R. tenuis the inflorescences are upright with straightly patent branches. Ecologically R. graminea occurs in relatively dry grasslands on sandstone or crystalline base, while R. tenuis is a typical marsh species. The specimens cited above mark a considerable range extension of this rare species from Suriname into Venezuela, Guyana, and Brazil.

Distribution:Venezuela South America| Guyana South America| Suriname South America| Brazil South America|