Background:

The family Fagaceae is one of the most important in temperate regions of the Northern hemisphere. Fagus and Quercus are distributed in Mexico, the former in Northeastern Mexico, while the latter reaches a high diversity in the Sierra Madre Oriental, Mexico. In Hidalgo state, located mainly in the Sierra Madre Oriental, knowledge of the Fagaceae diversity is still uncertain.

Questions and/or hypothesis:

We carried out a taxonomic revision of the genus and species of Fagaceae in Hidalgo state. We determined how many and which species are distributed in Hidalgo. We also present a morphological description and ecological characters of each one.

Studied species:

The species of the family Fagaceae.

Study site:

Hidalgo state, Mexico.

Method:

We collected herbarium specimens, made field observations and reviewed herbarium data of Fagaceae specimens at FCME, INEGI, MEXU, ENCB, SLPM, HUAP, HUMO, XAL and partly BH herbaria. In addition, we checked taxonomic literature and protologues of each species.

Results:

We found one species of Fagus and 43 of Quercus, 22 of which belong to the section Quercus (white oaks) and 21 to section Lobatae (red oaks). Morphological descriptions, altitudinal and geographical distribution, vegetation types of each species and a dichotomous key for species identification are presented. Illustrations and photographs of the species are also included.

Conclusions:

A high diversity of Fagaceae species is present in Hidalgo state. In Mexico, Hidalgo ranks in fifth place for oak species diversity, just behind Oaxaca (50 species), Puebla (50), San Luis Potosí (45), and Jalisco (45).