Ultrastructure and chemistry of epicuticular wax crystals in Polytrichales sporophytes

Results of scanning-electron-microscopic and chemical investigations of the epicuticular waxes on some Polytrichales sporophytes are presented. In Atrichum, Oligotrichum, Polytrichum, Pogonatum (Polytrichaceae) and Dawsonia (Dawsoniaceae) short wax tubules were observed, corresponding to the epicuticular crystal shapes of most gymnosperms and some angiosperms. In some species they extend into helical appendices. The composition of cuticular waxes on sporophytes of Pogonatum belangeri and P. urnigerum (n-alkanes, n-alkyl esters, n-alkanals, primary n-alkanols, and n-alkanoic acids) closely resembles that of moss gametophytes and of higher plants. The dominating compound, nonacosan-10-ol, is shown to constitute the tubular wax aggregates. Possible functional aspects of epicuticular wax crystals on mosses and their convergent or original evolutionary character are discussed.