Importance of Intermittent Shade to the Ecophysiology of Subalpine Herbs

We report here on the importance of intermittent shade periods for improving water relations and, thus, daily carbon gain in two subalpine understorey herbs. Data on carbon assimilation and plant water status during intermittent sun/shade periods and continuous full sun periods are presented for Arnica latifolia and its congener, Arnica cordifolia. The apparent importance of natural shade periods to the physiological performance and differences in small-scale distribution patterns between the two congeners is discussed