PERITHECIUM DEVELOPMENT IN PODOSPORA-TETRASPORA AND PODOSPORA-VESTICOLA

Perithecium development in Podospora tetraspora and Podospora vesticol a begins as ascogenous cells which are quickly enveloped by growth of sterile hyphae to form the young perithecium. At a later stage these t issues begin to differentiate, the outer peridial pseudoparenchyma bec omes pigmented and the ascus initials are embedded in small-celled pse udoparenchyma which fills the centrum. A surrounding jacket of large p seudoparenchymatous cells (=jacket paraphyses) encases the centrum. Th e agent(s) which brings about the formation of the periphyses also aff ects the upper cells of both the pseudoparenchymatous jacket tissue an d central pseudoparenchyma, such that the end cells disassociate from one another and the jacket tissue assumes a free-ended appearance. At maturity, the asci grow up between central elongated pseudoparenchymat ous tissue which becomes obliterated during this process, and may serv e a nutritive function. The jacket paraphyses remain, encasing the asc i and forming an inner lining to the perithecium. Perithecium developm ent in these two closely related fungi differs from that which has bee n described for some related species.