Abstract
This paper deals with the habitat of Sphagnum girgensohnii Russ. which occurs usually in subalpine forests in Japan. The habitat of S. girgensohnii was investigated at 32 sites of different topographical conditions in a subalpine coniferous forest of Mts. Yatsugatake, central Japan. Sphagnum girgensohnii forms discrete colonies at the forest floor, and occurs much more on the lower part of the slope. In this area, there is a considerable differentiation in their microrelief caused by lave flows or boulders. Sphagnum girgensohnii is restricted to the hollows. The forest floor is generally covered with humus. Sphagnum girgensohnii grows on thicker layers of humus than other bryophyte species. The result obtained from this study suggests that soil surface moisture is a limiting factor in the formation and maintenance of colonies of S. girgensohnii.
