Monographs Details: Mapaniopsis effusa C.B.Clarke
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Cyperaceae
Description:Distribution and Ecology - Known only from a few localities in southeastern Arenezuela and adjacent Brazil. VENEZUELA. Bolivar: Cerro la Danta, NW of Cerro A'enamo, wooded quebrada on northern slope, headwater of Rio Venamo alt 1600 m, Steyermark A Xilsson 46 (USl; Cerro A'enamo, Rio Venamo, alt 9501400 m, Steyermark et al 92317; Cerro Venamo, affluence of the east river of Rio Venamo, along quebrada leading to waterfall, alt 1400-1450 m, Steyermark et al 92643. Mapaniopsis effusa, hitherto known only from Rio Negro region of Brazil, is apparently a new addition to the flora of Venezuela.

Discussion:

Type. Brazil. Prov. Rio Negro, Barra, R. Spruce 2017 (K).

This remarkable species is at once recognized by its scirpoid habit, i.e., the tall, several-noded, leafy culms and large, open umbelliform corymb bearing numerous minute spikelets and many leaf-like involucral bracts. Mapaniopsis effusa and Diplasia. karataefolia, both representing a monotypic genus in the neotropics, exhibit primitive morphological features of the tribe Mapanieae particularly in their open inflorescences, whereas Scirpodendron ghaeri, which represents another monotypic mapanioid genus in the Old World tropics, retains its primitive feature in the structure of spikelets. Phytogeographically, the tribe Mapanieae thus shows two centers of differentiation, one in American Guayana and the other in Malaysia.

Distribution:Venezuela South America| Brazil South America|