Carbon and hydrogen isotope ratios of bryophytes from arid and humid regions.

Measurements of carbon isotope ratios of nine taxa of arid zone mosses from North America and 24 taxa of European bryophytes show consistent values indicative of C3 metabolism. Other morphological, physiological and biochemical characteristics provide the mechanism of adaptation to environmental stresses of heat and extended desiccation in these plants. Analyses of D content indicate that values become less negative with increasing aridity of the habitat.