Monographs Details: Mabea argutissima Croizat
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Euphorbiaceae
Description:Distribution and Ecology - Small tree found between altitudes of 300-1400 m, Guayana Highland. BRITISH GUIANA. Cobanatuk Falls, Potaro River, Jenman 7440; 107 m, Bartica-Potaro road, small tree to 20 ft and 2 inch diam, red barked with whorled branching, from Kakarlli clump, wallaba forest on lateritic soil, F. 1442, FD 4178. VENEZUELA. Bolivar: Kavanayen, Selva de Oparuma, Lasser 1859; entre matorrales al borde de una pica, en los Brasileros, alt 450 m, zona de Ika-baru, Bernardi 6625; matorral de orilla de camino, campo diamantifero de Uai-paru, Zona de Ikabaru, 420 m, s.n.m., Bernardi 6668; Uriman, Rio Anac-apa afl. del Apacara, selva pluvial, alt 500 m, Bernardi 1526; region de los rios Icabaru, Hacha, y cordillera sin nombre a 280° de los cabaceros del Rio Hacha, alt 450850 m, Bernardi 2718, 2864; woods bordering savanna on ridge above La Laja at base of Sororopan-tepui, alt 1375-1460 ft, Steyermark 60816; Ptari-tepui, dense forest at base of Cerro along Rio Ivaruai, alt 1220 m, Steyermark 60638 (NY, US) ; tree 10 m high, rainforest in valley lowland between Rio Chicanan and Rio Ayaiche, between Puerto Lema and base of Sierra Cabecera de Rio Chicanan 80 km al sur-oeste de El Dorado, lat 6°5'N, long 62°W, alt 300 m, Steyermark 89438 (NY, US); Amazonas: en los sitios arenosos en la margen arboreada del bajo Rio Guainia, Playa Blanca, alt 127 m, Williams 14455 (US); en los margenes abiertas en la boca bel Cano Ichana, San Miguel, Rio Guaiania, alt 127 m, Williams 14882 (US); en la margen arboreada del Rio Orinoco, Tama-tama, alt 121 m, Williams 15102 (US); en los chiquichiquiales, Copihuara, Alto Casiquiare, alt 120 m, Williams 15724 (US); Cerro Duida, Rio Cunucunuma, small tree 4 m tall, flower heads greenish-white, Playa Alta, alt 100 m, Maguire, Cowan & Wur-dack 29450; tree to 15 m tall, bark smooth, brown, occasional, Playa Alta, alt 100 m, Maguire, Cowan & Wurdack 29465; rios Pacimoni-Yatua, Casiquiare, slender tree with white latex, fruit green, along Rio Yaciba, above mouth, alt 160m, Maguire, Wurdack & Bunting 36524 COLOMBIA. Vaupes: Rio Negro at confluence of rios Guiania and Casiquiare, Cano Ducuruapo (Igarape Rana), Schultes & Lopez 9393 (US).

Discussion:

Mount Roraima District, vicinity of Arabupu. Slender tree in second growth, 12 ft high, trunk 5 inch diam, fruit green, alt 4200 ft, Bolivar, Venezuela, Albert S. Pinkus 275 (isotypes US, NY, holotype A).

The typical, higher-altitude specimens show a remarkably stable character in the aristate crenation of leaf margin. Somewhat less typical in this respect are specimens originally along the Guainia river in Venezuelan Amazonas, Williams 14455,14882,15102 and 15724. There is a possibility that M. argutissima is identical with M. costata Pax & K. Hoffm. (Pflanzenreich 6: 419. 1914) of British Guiana. Croizat thinks it may turn out to be identical with M. subsessilis Pax & K. Hoffm. (Pflanzenreich 52: 282. 1912.) collected in Brazil, without specific locality by Glaziou (no. 10035). Either of these names would have priority over M. argutissima. In absence of types, this question must be left unanswered, and therefore I prefer to retain Croizat's name.

Distribution:Guyana South America| Venezuela South America| Colombia South America|