Resumen

ELY, Francisca; TORRES, Fresia  y  GAVIRIA, Juan. Relationship between leaf structure of three species of Miconia (Melastomataceae) and their habitat and altitudinal distribution in the Sierra Nevada National Park, Mérida, Venezuela. Acta Bot. Venez. [online]. 2005, vol.28, n.2, pp.275-300. ISSN 0084-5906.

In the Sierra Nevada National Park, in Mérida, three species of Miconia (Melastomataceae) occur between 3.000 and 4.000 m asl. These species are: M. chionophylla, M. latifolia and M. tinifolia. The first is a dwarf shrub of the Polylepis sericea forests, whilst the other two species are trees of the upper montane forests. With the purpose of describing and comparing these three species, their distribution and habitat, the morphoanatomical characters of the leaves were studied in samples collected from individuals growing at different altitudes, along this gradient. Miconia latifolia and M. tinifolia reach 3.500 m and exhibit typical xeromorphic leaves: reticulated vein pattern, thick cuticles, elevated stomatal density, small epidermic cells, multistratified hypodermis and a compact mesophyll. M. chionophylla, instead, exhibits typical mesomorphic leaves, characterized by a lax vein pattern and mesophyll, thin cuticles, relatively low stomatal density and lacks a hypodermis, yet reaches 4.000 m asl.

Palabras clave : Melastomataceae; Miconia; Leaf morphology; Leaf anatomy; Vein patterns; Venezuelan Andes.