328 CLASS ASCOMYCETEAE 



oogone but fusion of these pairs has not been observed. In the meantime 

 hyphal branches arising from just below the oogone form the beginning 

 of the perithecial wall which is one or two layers of cells in thickness. From 

 the base of the fertilized and enlarged oogone grow several ascogenous 

 hyphae, each of several dicaryon cells. The apical and second and third 

 cells may develop into asci, each with eight ascospores. Ascus walls and 

 the remainder of the ascogenous hyphae and of the oogone and antherid 

 dissolve and leave the ascospores free in the perithecial cavity. De Bary 

 (1870) and many years later Miss Dale (1909) reported that in Aspergillus 

 glaucus Lk. (= Eurotium herhariorum Lk.) a tightly coiled ascogonium 

 is formed, at first one-celled but soon dividing into several multinuclear 

 cells. An antherid rising from lower down or from another branch creeps 

 up the side of the coiled ascogonium. A fusion of antherid and ascogonium 

 was not observed and possibly does not occur. It is not certain that this 

 is really an antherid. Possibly it is one of the investing hyphae that grow 

 up from below the ascogonium to form the perithecial wall. Soon the 

 middle cells of the ascogonium divide into binucleate cells from which 

 arise the branched ascogenous hyphae. From the cells supporting the asco- 

 gonium arise the hyphae which form the perithecium with a cortex of one 

 layer of polygonal cells the interior being filled with thin-walled cells. In 

 the species called by Brefeld (1874) Penicillium crustaceum Ft., this 

 mycologist reports the formation of short coiled antherid and ascogonium 

 from adjacent cells of the same hypha. These fuse at the apex and give 

 rise to a several-celled structure from which branch out the ascogenous 

 hyphae while around them a dense sclerotium-like perithecium develops. 

 The nuclear behavior has not been followed. Dangeard (1907) reports in 

 P. vermiculatum Dang, that there is formed a long straight multinucleate 

 ascogonium around which coils a slender antheridial hypha with an en- 

 larged uninucleate antherid at the apex. This fuses with the ascogonium 

 and the male nucleus may pass into the latter or may remain in the 

 antherid. The ascogonium then divides into binucleate cells from which 

 arise the ascogenous hyphae. Dangeard reports that the male nucleus is 

 not functional. Derx (1925) reported that the ascospores in P, luteum 

 Zukal produced mycelia of two sexual phases that are mutually compat- 

 ible and self-sterile. 



Family Gymnoascaceae. This family is characterized by the lack of 

 a firm-walled perithecium, this })eing represented by a more or less loosely 

 tangled mass of mostly branched hyphae among the bases of which the 

 asci are clustered. When mature they are usually visible through this 

 tangle of hyphae. The chief generic distinctions are based upon the 

 character of these interwoven filaments and the color of the ascospores. 



The ascocarps are mostly not over 1-2 mm. in diameter, often smaller, 

 and sessile, globose or depressed globose, almost colorless or dark-colored. 



