Los encinos del Parque Nacional Los Mármoles, Hidalgo, México

knowledge of species richness of quercus in mexico is incomplete due mainly to its wide distribution, high intra-species morphological variability and its capacity for forming hybrids, making taxonomy of the genus difficult. the objective of the present study was to examine the floristic composition of species of genus quercus in los mármoles national park (pnm) and their distribution in the study area. this park is the second-largest natural protected area in the state of hidalgo, mexico. specimens of oak were collected at 36 sites along elevation gradients. identification of the material enabled recognition of 18 species of oak growing in the park, including quercus furfuracea liebm., recorded for the first time in the state of hidalgo. the species with the greatest distribution in the park were quercus affinis scheidw., q. crassifolia humb. and bonpl., q. laeta liebm. and q. mexicana bonpl. knowledge of oak species richness and distribution can serve as a reference for the establishment of forest management and conservation programs in the pnm.