616 



MEDICAL MYCOLOGY 



unknown whether sexual organs are produced in this mass, but the system of 

 ascogenous hyphae develops in it (Fig. 96). Very interesting results are ex- 

 pected from further work on this group in progress by Emmons. 



Perithecia are frequently formed in Aspergillus, very rarely in Penicillium. 

 In most of the species so far studied, their appearance is preceded by the for- 



1 



Fig. 95. — Gliocladium roseum. 1, diagram of phialide of the Clonostachys type; 2, 

 Acrostalagmus type ; S, Penicillium type ; 4, more typical structures, showing- various stages in 

 the formation of the penicillus which becomes a gelatinous mass of conidia. 



Fig. 96. — Penicillium Brefeldianum. l-l), development of conidiophores 

 from ascogenous hyphae. (After Shear.) 



5, growth of ascl 



mation of sexual organs. They may be arranged in four groups, depending 

 on the reported methods of perithecial development. In the first group, as in 

 Aspergillus nidulans, two equal copulatory branches are formed ; they coil 

 around each other helically and apparently fuse at the tip (Fig. 97, 1-3). The 



