Abstract: Moss-dominated crusts play important roles in ecological restoration in hilly Loess Plateau region, China. Four dominant moss species Didymodon vinealis (Brid.) Zand., Didymodon tectorum (C. Mull.) Saito, Barbula unguiculata Hedw. and Bryum argenteum Hedw. in the community of biological soil crusts in the hilly Loess Plateau region were chosen as objects. The morphological and anatomical structure of the four moss species were observed and measured in this study. The results showed that D. vinealis had greater shoot height (6.1 mm), stem diameter (298.6 μm), midribs width (65.5 μm), leaf width (590.9 μm) and blade thickness (14.8 μm) than the other three species; the stem epidermis cell wall of D. vinealis was obviously incrassate and the cortex cells were distributed in a mosaic pattern. D. tectorum did not show significant advantages in its stem and leaf structure. With coarse stems and leaves, D. vinealis had stronger desiccation tolerance than the other three species, and thus it was easy to adapt to the variability of environmental moisture. The leaf length (3.2 mm) and basal leaf cell size (191.2 μm²) of B. unguiculata were significantly higher than that of the other three species and contained much more chloroplasts. Their midribs were in sharp “v” form, and this morphological structure was closely related to their water harvesting. In B. argenteum, the cortex cell area was 987.8 μm², and single cortex cell accounted for approximately 3.1% of stem transversesectional area. The leaf hair (274 μm) was significantly longer than that of the other three species and the upper leaf cells and leaf hair of this species were transparent, which endows it to grow in the conditions with periodical drought stress and to resist light radiation. Our study suggested that the differences in stem and leaf morphological structure existed among the four moss species, with different adaptation to various water and light conditions, which may reflect their ecological adaptability. Also, this study may provide reference for species selection in restoration of moss crusts.

Key words: agroecosystem health, spatial-temporal pattern, factor diagnose