Abstract
A threatened plant, Ixeris tamagawaensis Kitam. is in strong concern about its extinction. So we surveyed the habitat traits of this plant along Tama River. We set six belt transects and checked trough the number of individuals of I. tamagawaensis and the six factors of environment. These factors are 1) height from water level, 2) distance from brink, 3) percentage of vegetation coverage, 4) percentage of sediment cover, 5) percentage of litter cover, and 6) dominant species. The results means that I. tamagawaensis grow at dry riverbed characteristically. Regardless of that, the area of dry riverbed is decreasing. Accordingly, we recommend conserving the dry riverbed urgently.
