The relationships between climatic conditions, ecological features and distribution were investigated for the mosses Trachycystis flagellaris and T. microphylla in Niigata Prefecture, central Japan. T. flagellaris is frequent in the interior mountainous areas, and is considered to require high moisture for its growth. Its distribution is restricted to areas where Kira's Warmth Index (see Kira 1976) is 50-65 and summer precipitation is 550 mm or more. Production and maturation of sporophytes are well adapted to lower temperature and deep snow at higher altitudes. On the other hand, T. microphylla is frequent in the coastal lowlands. Its distribution is restricted to areas where Kira's Warmth Index is 95 or more and the summer precipitation is 400-440 mm. Its substrate selectivity and the associated vegetation in its habitat show that this moss is well adapted to habitats that are well drained. As its sporophyte maturation occurs in early spring, the distribution of its sporophyte may be restricted to the coastal lowlands where the snow cover is thin in the winter.

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Two species of Aloina, A. rigida (Hedw.) Limpr. and A. obliquifolia (C. Muell.) Broth., are added to the moss flora of Japan. Both species were found in the limestone area in Hase-mura, Nagano-ken, central Japan. Detailed descriptions and figures of these two species are given.

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Genetic variation within, and divergence among, populations of two liverworts, Riccia fluitans and Ricciocarpos natans, both of which have been regarded to reproduce mainly asexually, were assessed by starch gel electrophoresis. Here Riccia fluitans is defined in the broad sense as a taxon that bears a single row of ventral scales and has a chromosome number of n=8. The following twelve loci were detected for Riccia fluitans (Aat, Acn, Ald, Idh, Me1, Me2, Pgm1, Pgm2, Skdh, Sod, Tpi1, Tpi2). Fifteen loci (Aat, Acn, Ald, Gdh, Lap, Mdh1, Mdh2, Me1, Me2, Pgm1, Pgm2, 6pgd, Skdh, Tpi1, Tpi2) were detected for Ricciocarpos natans. Riccia fluitans showed little or no genetic variation within each population. On the other hand, a total of 13 multilocus genotypes were distinguished on the basis of five polymorphic loci (Table 1). There was no relationship not only among these multilocus genotypes but also between the two distinct forms, that is, landand water-forms. Ricciocarpos natans showed only slight genetic diversity among populations and little or no variation within each population (Table 2). In addition, two fertile populations (Niigata Pref., Mikawa and Sawata) were examined; there was no genetic variation within these two populations for 15 loci examined.

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