434 



BOTANY OF THE LIVING PLANT 



mycelium permeates any nutritive medium ; thus they serve for the 

 quick spread of the Mould. The corresponding conidiophores of 

 Penicillium are constructed on a similar plan, but are 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 chain of conidia is abstricted, as before (Fig. 366). 



The alternative method of propagation follows in Aspergillus on 

 a rise of temperature, and results in those yellow fruits originally 



FIG. 367. 



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

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

 magnified. 4, ascospores. (After Brefeld.) 



described under the name of Eurotium. When ripe each contains 

 numerous asci, and spores. Similar fruits are formed also in 

 Penicillium, but more rarely. The development originates in either 

 case from a spiral or twisted carpogonium, 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 carpogonium 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 Aspergillus (Fig. 3^7)- 1 



