Monographs Details: Mapania pycnocephala subsp. fluviatilis (Sandwith) T.Koyama
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 - Guianas and adjacent Amapa, westward to eastern Amazonas of Venezuela, Brazil; one isolated locality in Paria Peninsula of Venezuela. VENEZUELA. Sucre: Paria Peninsula, Cerro Patao, N of Puerto de Hierro, NE of Guiria, alt 1020 m, Steyermark A Agostini 91091; the same locality, alt 850 m, Steyermark & Agostini 91018; Bolivar: Alto Rio Cuyuni, frequent in montane forest between base of La Escalera and Base Camp, alt 150-550 m, Maguire, Steyermark & Maguire 46941; Amazonas:Cerro Marahuaca, alt 1000 m, Maguire & Maguire 29190. BRITISH GUIANA. Potaro River, by mouth of River Ewang, alt ca 2000 ft, Whitton 15 (K); Pakaraima Mts., Upper Mazaruni River, Eagle Mountain, mixed woodland on laterite soil at alt 300 m, Maguire & Fanshawe 32093. BRAZIL. Amapa: Serra do Navio, Rio Amapari, herb of swampy area along trail to Rio Araguarv, alt 70-300 m, Cowan 38439.

Discussion:

Type. Conawarook River, British Guiana, A. W Bartlett 8242 (K)

When Sandwith described Mapania fluviatilis from British Guiana, he separated it from the quite different M. macrophylla, but failed to compare it with M. pycnocephala with which Sandwith’s plant had real affinity. In every respect, Atlantic M. fluviatilis closely resembles Pacific M. pycnocephala. The two plants, which cannot lie separated by vegetative characters, differ only in the minor details of flowering parts (see Fig. 14 A-H). The fructifications of M. fluviatilis appear to be slightly larger than those of M. pycnocephala because of the somewhat broader margins of the angles. In M. fluviatilis slightly larger glumes at 6.5-7 vs 5-6 mm in length are generally glabrous on the median portion, while in M. pycnocephala the glumes are generally pubescent on the upper portion. The brown color of glumes tend to be darker in M. fluviatilis than in M. pycnocephala. The distinctions of pubescence and coloration of glumes, however, are not clearcut because of the presence of intermediate plants in the Venezuelan Guayana. Emphasizing the geographical discontinuity which corresponds to the morphological differences M. fluviatilis is here reinterpreted as a subspecies of M. pycnocephala.

Distribution:Venezuela South America| Brazil South America|