MORPHOLOGIC AND HABITAT ANALYSIS OF Quercus glabrescens x Q. rugosa HYBRID

Abstract

Quercus species are prone to form hybrids very frequently in different parts of the world. The Quercus glabrescens x Q. rugosa hybrid was studied in terms of habitat (geographic distribution and species association) and of the Morphologic Hybridization Index. With the distribution of Q. glabrescens and Q. rugosa was obtained a bioclimatic model of minimum average temperature and winter rainfall per cent. At El Chico National Park, Hidalgo State, Mexico, eight lots were surveyed and in each of them was determined frequency, cover, basal area, stem volume and dominance index of the tree species. Ten morphologic characters were assessed in 50 examples (alleged hybrids). The bioclimatic model showed that Q. glabrescens has a greater preference for zones where low minimum average temperatures prevail and with winter rainfall per cent higher than Q. rugosa. A common zone with ecologic affinities was found. Through Pearson correlation and the Principal Component Analysis, diverse habitats were detected with species association and hybrid category. Trees with a tendency for Q. glabrescens or in-between were found. The first showed ecologic affinities similar to Q. glabrescens and the second expressed flexibility. Evidence is reported about the natural hybridization between Q. glabrescens and Q. rugosa.