STUDIES ON THE MORPHOLOGY OF SYNNEMATA OF HIRSUTELLA GIGANTEA PETCH

Abstract

The morphology of the synnemata produced by Hirsulella gigantea has been investigated using histological techniques. Dark-colored initials are formed within the aerial mycelium by a proliferation of differentiated hyphae. Development of the synnemata continues by an elongation in a direction away from the nutrient agar. As the synnemata grow, the hyphae become oriented in a longitudinal direction. At maturity only the outer coat consists of differentiated hyphae; the bulk of the structure is formed of normal mycelium. Sporogenous cells form on the outer coat and bear conidia, commonly in pairs, within a drop of mucus. The synnemata formed by H. gigantea are compared with those produced by Isaria cretacea and Penicillium claviforme. Some similarities are found, especially during the early stages of development.Three other forms of fruiting bodies were observed in cultures of H. gigantea grown under unusual conditions. Two of these forms were sterile.