Spore morphology of two species of Trematodon and two of Microcampylopus were observed and studied by Scanning Eledtronic Microscope(SEM) for the first time in China. All spores of both genera are spheroid and characterized by obvious differentiation of distal and proximal surface and distinct ornamentation with large bacula,spinose process or tumors.In a genus,differences of size and ornamentation between two species are distinct and can be used as taxonamic characters on species level. The spores of T.ambiguus and T.longicollis are 19.1-18.8um and 20.5-20.2um,respectively. Distal surface of T.ambiguus are covered with coarse spinate process up to 2.5-4um. The proximal surface has obvious tetrad surrounded by a convex circle with fine verrucae on it. The distal surface of T.longicollis are covered with large bacula,while proximal surface with no distinct tetrad surrounded by a circle formed by regular bacula and covered with relatively small bacula on it. The spores of Microcampylopus laevigatus and M.kasianus are 21.9-20.5um and 19.2-18.6um,respectively.The distal surface of spores of both two species are covered with large tumors,but the tumors of M.laevigatus are much larger and more irregular in size than those of M.kasianus.In addition,the proximal surface of M.laevigatus is distinct and surrounded by a few large verrucae and covered with dense and small granules,while that of M.kasianus is not distinct and covered with small verrucae.

Key words: Dicranaceae, Microcampylopus, Mosses, SEM, spore morphology, Trematodon