ASCOMYCETES 



423 



Mould. The corresponding conidiophores of Penicillium are con- 

 structed on a similar plan, but arc much smaller. Instead of bearing 

 a mop-like head, they are repeatedly branched, giving them a brush- 

 like appearance, while from the end of each branch a basipctal chain 

 of conidia is abstricted, as before (Fig. 320). 



The alternative method of propagation follows in Eurotium on 

 a rise of temperature, and results in the production of small yellow 

 fruits. When ripe each contains numerous asci, and spores. Similar 



Fig. 321. 



i, Section through part of a fruit of Penicillium ; a, b, pseudo-parenchyma toils 

 covering ; d =ascogenous hyphae. 2, 3, ascogenous hyphae with asci, more highly 

 magnified. 4, ascospores. (After Brefeld.) 



fruits are formed also in Penicillium, but more rarely. The develop- 

 ment originates in either case from a twisted oogonial branch, which 

 is associated with an anther idium. As in Sphaerotheca these sexual 

 organs become enveloped in a pseudo-parenchymatous covering, 

 derived from the mycelium that bears them. The oogonium divides 

 into a number of cells, from which strong hyphae arise. These are 

 nourished by the surrounding tissue, and produce the numerous oval 

 asci, each with eight ascospores. In Penicillium the structure of the 

 fruit-body is more complicated than in Eurotium (Fig. 321). In 

 either case the result at ripeness is that the fruit appears as a dry 

 spherical sac, filled with ascospores set free by the disappearance of 



