Biological and physiological characteristics of Neotyphodium gansuense were compared with Neotyphodium coenophialum and Epichloe festucae at a range of temperatures and pH values, and on carbon and nitrogen amended media. N. gansuense was able to grow at 10-30 1C, but not at 51C, and slowly at 351C. The optimal temperature for both N. gansuense and N. coenophialum was 251C, but that of E. festucae was 20-25 1C. The optimal pH ranges for mycelial growth of N. gansuense, N. coenophialum and E. festucae were 5-9, 5-9 and 5-7, respectively. The Neotyphodium and Epichloe