Growth of fruit-bodies inFavolus arcularius

The fruiting ofFavolus arcularius in culture is described. When the cultures, which have been pre-incubated in darkness to allow the inoculum mycelia to become thick and white wooly in texture, are exposed to light, fruit-body primordia, 1 mm in height, are formed about 4 days after the start of illumination. The primordium develops into a cylindrical stipe, the growth of which mainly occurs in the final 1 mm of the terminal region. Hyphal elongation in the region within 3 mm of the apex is predominant in the growth of the pileate stipe. With maturation of the stipe, changes in hyphal orientation occur on the periphery of the subapical region, and then the pileus-primordium is formed. The differentiation into the inner layer and the outer layer (pre-hymenial layer) in the pileus tissue is completed at this stage. The early growth of the pileus may be due to rapid elongation of the hyphae on the margin in addition to gradual expansion of the hyphae in the preformed pseudo-tissue. When the pileus has grown to about 3 mm in diameter, the subsequent three to four fold increase in size may be due to parallel expansion of the hyphae constituting the young pileus tissue.