Abstract

ELY, Francisca; TORRES, Fresia  and  GAVIRIA, Juan. Leaf morphology and anatomy of Monochaetum meridense (Melastomataceae). Acta Bot. Venez. [online]. 2005, vol.28, n.2, pp.197-212. ISSN 0084-5906.

Monochaetum meridense (H.Karst.) Naudin is a widely distributed shrub of the South American Andes, however, the studies carried out for this species are restricted to a few morphological descriptions and floristic surveys. This motivated the authors to describe the leaf structure, and if possible, to relate it with the species habitat and distribution along a gradient in the Sierra Nevada of Mérida, a relatively undisturbed mountain range that comprises cloud forests, upper montane-forests (bosques parameros) and páramo vegetation. M. meridense grows between 2.400-3.400 m asl, it presents a thin cuticle, a scarce content of schlerenchyma, lax spongy parenchyma and vein pattern, characters that depict M. meridense as a mesophyte, however, the tall and thickened anticlinal walls of the upper epidermic cells, along with the well differentiated mesophyll and compact palisade parenchyma, suggest a heliophyte conduct and explain the species preference for sunny environments along this gradient, in which no significant differences were observed among the individuals growing at different altitudes.

Keywords : Monochaetum meridense; Leaf anatomy; Vein pattern; Heliophyte; Cloud Forest; Venezuela.