On the ecology of Thelypteris limbosperma in W Norway. The distribution in relation to climatic factors

In 31 selected districts in W Norway the vertical distribution of Thelypteris limbosperma has been recorded. Special attention has been paid to the area within which T. limbosperma occurs as a dominant in the vegetation. Both horizontal and vertical distribution areas are related to climatic factors, namely the mean temperature of the wannest and coldest months, precipitation and humidity conditions expressed by Martonnes aridity index. Correlations between the distribution of T. limbosperma and these parameters have been elucidated. In oceanic districts correlations exist between the vertical distribution limits and the mean temperature of the warmest month, t. max = 14.2°C and 10.3°C. In suboceanic districts correlations are with t. min = -5.3°C, P = 121 mm; and H = 87.0. In districts where H < 60 the fern is sparce or missing.