CORTICOLOUS BRYOPHYTES FROM THE OAK-WOODS OF SIERRA-DE-GREDOS (AVILA, SPAIN)

Based on the study of more than 600 samples collected in 5 deciduous oak-woods from both faces of Gredos Range, a catalogue of 51 corticolous taxa (8 hepatics and 43 mosses) is presented. Among the factors accounting for so high a richness in epiphytic bryophytes in a mediterranean environment, the most relevant are: a large representation of the genus Orthotrichum (10 species) and a high number of facultative epiphytes which, from surrounding rocks or soil, colonize tree bases or trunks. Finally, comments are devoted to the differences shown by some bryophytes in bark colonization along the Spanish Central Range. 13 new records and 20 second ones are reported for the province of Avila.