Abstract

The exostome structure of Brachytheciaceae was studied with the scanning electron microscope. 63 species of 17 genera were involved: Brachythecium (21 species), Bryoandersonia (1), Camptothecium (2), Cirriphyllum (1), Eurhynchiella (1), Eurhynchium (9), Homalotheciella (1), Homalothecium (5), Myuroclada (1), Palamocladium (2), Platyhypnidium (4), Rhynchostegiella (6), Rhynchostegium (5), Scleropodium (2), Scorpiurium (1), Steerecleus (1). Rhynchostegiella, Homalothecium and Homalotheciella have many advanced characters, mostly clearly adaptive to xeric environments. Exostome patterns provide evidences for the segregation of Camptothecium from Homalothecium, Platyhypnidium from both Rhynchostegium and Eurhynchium, Steerecleus from Rhynchostegium, Eurhynchiella from Rhynchostegiella.