Peristome variations in the genus Fissidens: an SEM [scanning electron microscopy] study [Musci]

Peristomes of 19 species representing two subgenera of the genus Fissidens were examined using scanning electron microscopy. Seven types of peristomes were distinguished on the basis of variations in the trabeculae and the lamellae of the dorsal and ventral surfaces. These seven types are designated the scariosus-, bryoides-, excurrentinervis-, obtusifolius-, taxifolius-, subbasilaris-and manateensis-types of peristomes. In some instances, species having similar peristome types are gametophytically similar; in other instances species having the same peristome type have different gametophytes. In still other instances, species with dissimilar peristome types have similar gametophytes.