Despite its small area (7500 km2), the Valle de México is the site of high plant diversity. Its flora includes about 105 species and varieties of pleuocarpous mosses, i.e., 31% of the total recognized for Mexico. The Leucodontales include 22 taxa, the Hookeriales are represented by two species only, and the Hypnales by some 81 taxa. Because of their epiphytic habitat, the Leucodontales are comparatively scarce in the Valle de México; the Hookeriales usually grow in lowland, shaded moist tropical forests. The large and diverse Order Hypnales is a north temperate taxon which, in the tropical latitudes, is distributed at high elevations in open forests that are frequent in the area of study. Drepanocladus capillifolius and Hygroamblystegium fluviatile are recorded for the first time for Mexico.