Resumen:
A new species, Orthotrichum vittii F. Lara, Garilleti, & Mazimpaka (Orthotrichaceae, Bryopsida) is described. The new taxon, close to Orthotrichum diaphanum Brid. and O. macrocephalum F. Lara, Garilleti, & Mazimpaka, is characterized by leaf apices with short hyaline awns, leaf areolation firm and not bulging, capsules emergent and strongly ribbed, stomata cryptoporous, exostome with eight pairs of teeth that are recurved when dry, endostome with 16 thin segments that are incurved and frequently appendiculate, and prostome occasionally present. It is distributed throughout Spain, especially in the eastern half, and is a xerophytic epiphyte with marked preferences for mountainous-continental Juniperus thurifera forests.