ENDOPHYTE-HOST ASSOCIATIONS IN GRASSES .20. STRUCTURAL AND REPRODUCTIVE STUDIES OF EPICHLOE AMARILLANS SP-NOV AND COMPARISONS TO E-TYPHINA

Morphological and reproductive studies were made on five populations of Epichloe amarillans sp. nov. occurring on the host grass Agrostis hiemalis. The fungus was found to be similar to Epichloe thphina in ejection of filamentous ascospores without prior disarticulation. However, differences are evident in several features, including size and density of perithecia, and size of asci and ascospores. Crosses to stromata of E. amarillans were made using selected isolates of several species of Epichloe and stromata of E. amarillans from the five different populations. Perithecia developed in some of the crosses between different populations of stromata, which is evidence that mating types are present among the populations sampled. Perithecia developed in all intraspecific crosses involving a culture of E. amarillans isolated from a perithecial stroma, regardless of the mating type of the recipient stroma. This is taken as evidence that the culture is composed of a dikaryotic mycelium. A culture of E. typhina, similarly isolated from a perithecial stroma on Dactylis glomerata L., failed to produce perithecia in any cross.