Fig. 11.117. Arundinula abyssicola. A. Developing thallus tip with a reflexed secondary spore mother-cell. B. Secondary infestation sporangiospores seen developing inside their individual sporangia. C. Tip of a thallus that developed from a primary infestation sporangiospore, beginning to form septa so as to produce sporangia. D. Thallus tip with primary infestation sporangiospores. From Van Dover and Lichtwardt, 1986.