ASPERGILLACEAE 



617 



contents of one copulatory branch migrate into the other. Both are then sur- 

 rounded by a dense hyphal knot, which subsequently assumes a plectenchyma- 

 tous character (Fig. 97, 4-7). Here copulation is isogamous as in many Endo- 

 mycetaceae and Gymnoascaceae. 



The second group is typified by Penicillium Wortmanni (P. vermiculatum) . 

 The hyphae are always uninucleate. The ascogonium appears as a branch of 

 a hypha. Its single nucleus rapidly divides until the cell is 16-nucleate. The 

 antheridium, a slender branch arising on a different hypha, coils several 

 times about the ascogonium and abjoints a uninucleate apical cell which swells 

 slightly (Pig. 98, 1). Meanwhile the number of nuclei in the ascogonium has 

 reached about 64. The apical cell of the antheridium fuses with the ascogo- 

 nium (Fig. 98, 3). Dangeard (1907) was unable to see nuclear migration and 

 concluded that the male nucleus remains in the antheridium and degenerates. 



Fig. 97. — Aspergillus nidulans. 1, conidiophore showing- primary and secondary phialides ; 

 t, section of perithecium, showing asci and perithecial wall ; S, perithecium ruptured ; i, young 

 ascl; 5, germinating ascospores (J X230 ; 2 Xl70 ; S X85 ; h X400). (Alter Eidam 1883.) 



k 



The ascogonium then divides into numerous binucleate cells, each of which 

 may develop aseogenous hyphae (Fig. 98, 4-7). Here we have a morphologic 

 differentiation of antheridium and ascogonium; the appearance of the anther- 

 idium is retarded and if Dangeard correctly observed the normal develop- 

 ment, its single nucleus has become functionless. 



The third group may be typified by Apergillus herhariorum, A. repens and 

 A. fumigatoides. The ascogonium develops as a hyphal branch, and coils in a 

 helix with a continually shortening radius. It is divided into two or more 

 multinucleate cells of which the terminal is generally the longest and contains 

 about 20 nuclei. Shortly before or after the septation of the ascogonium, the 

 antheridium appears and climbs along the ascogonial helix. Many times it 



