180 



COMPARATIVE MORPHOLOGY OF FUNGI 



in Aspergillus nidulans (Eidam, 1883; Dangeard, 1907), as in Eremascus, 

 two equal copulation branches are formed; they coil around each other 

 helically (Fig. 117, C) and apparently come into open communication at 

 the tip. The content of one branch migrates into the other. Both copula- 

 tion branches are then surrounded by a dense hyphal knot (Fig. 117 D), 

 which subsequently assumes a plectenchymatous character. Thus in 

 these forms antheridium and ascogonium are still equivalent and may be 

 directly ranked with the equally isogamous copulation branches of many 

 Endomycetaceae and Gymnoascaceae. 



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Fig. 113.- — Penicillium vermiculatum. 1. The multinucleate ascogonium and young 

 antheridium. 2. The antheridium is in open communication with the antheridium but 

 the male nucleus remains in the antheridium. 3. The ascogonium surrounded by sterile 

 hyphae is divided into binucleate cells which are beginning to develop ascogenous hyphae. 

 (X 600; after Dangeard, 1907.) 



In a second group, which at present includes only Penicillium vermic- 

 ulatum (Dangeard, 1907), the copulation branches, as in P. "crustaceum," 

 are arranged regularly; however, they show a characteristic differentia- 

 tion in their behavior. In this species the hyphae are always uninucleate. 

 On the formation of the perithecium there appears, as a branch of any 

 hypha, a unicellular ascogonium rich in protoplasm, which, like the other 

 cells of the hypha, contains a single nucleus. It elongates rapidly and by 

 repeated nuclear division becomes as much as 16-nucleate. Meanwhile 

 there has appeared a second slender branch, the young antheridium. 

 Generally it arises from a different hypha than that which bears the 



