THE DISTRIBUTION OF EPICHLOE-TYPHINA IN NATURAL PLANT-POPULATIONS OF THE HOST-PLANT CALAMAGROSTIS-PURPUREA

The distribution of the systemic fungus Epichloe typhina was studied i n natural populations of the host grass Calamagrostis purpurea. By sea rching for stroma in field and dissecting and staining plant parts in the lab I found that E. typhina was only present in nutrient rich and more wet habitats and totally absent from nutrient poor areas. A green house experiment showed that under high nutrient conditions infected p lants produced significantly more shoots than did healthy plants, whil e no difference was found when plants were grown in low nutrient condi tions. Thus, the results suggest that the occurrence as well as the ef fect of E. typhina is strongly affected by environmental factors simil ar to the case of other systemic diseases, such as rusts and smuts.