Decomposing wood forms the substrate for special lignicolous, hygrophilous, and sciophilous plant communities. In a moist tropical forest, vegetation on this substrate consists mostly of bryophytes. The material gathered from Mt. Meru and the Usambara Mts. in Tanzania comprises 102 taxa or genera of bryophytes. Of these 86 taxa are mosses and 16 hepatics. They were collected from a number of rotten logs at different stages of decay both in primeval and in cultivated forests. The bryophyte vegetation on these logs was examined by use of quadrats 20 x 20 cm. A total of 71 taxa occurred in 51 plots
