Mabea eximia Ducke

  • Authority

    Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.

  • Family

    Euphorbiaceae

  • Scientific Name

    Mabea eximia Ducke

  • Description

    Species Description - Mabea eximia is a beautiful species, outstanding by its large inflorescence, 15-20 cm long, 6-8 cm across, in which both the male cymules and the female flowers are subtended by narrowly linear-subulate bracts attaining a length of 2-2.5 cm under the female flowers and 0.5-1 cm under the cymules. The pedicels of the 3 flowers are free for a length of 1 cm, and connate for the lower 2 cm, forming little 3-flowered umbels. The bracts and their two narrow longitudinal glands are somewhat elevated along the rachis, but the elevation seems to vary, being longer on the Amazon Valley specimens and shorter on the Guayana specimens. The capsules, heretofore undescribed, are trilobed, 3 cm across, 2-2.5 cm high; no central columella left after the segments fall off. Seeds are 11 mm in diameter, subspherical.

    Distribution and Ecology - A beautiful tree up to 10 m high or a high-scandent liane of the Amazon Valley in Brazil, British Guiana and State of Bolivar, Venezuela.

  • Discussion

    Type. Rio Tapajoz (Para) ad rivum Botica, regione cataractorum Mangabal, silva inundata, A. Ducke 17715 (isotype US, photo NY).

    Although I have not seen M. pulcherrima Mull.-Arg. [Flora 55: 44. 1872 or M.piriri var concolor Mull.-Arg. in DC., Prodr. 15(2): 1150. 1866 prop.], the detailed description of Muller-Argoviensis indicates that they are closely related to if not identical with M. eximia. To this close relationship Ducke himself called attention. Whether or not they are identical cannot be decided without seeing Deprieur’s type (“Guayana gallica” in herb. DC.). For the time being I prefer to keep them apart. Ducke also compared M. eximia with M. speciosa. In my opinion M. speciosa of the Rio Negro region is very distinct by its dictyodromous nervation and much narrower thyrse (only 3.5-4 cm across) and is more closely related to M. caudata or M. saramaccensis.