ASCOMYCETES.- 137 



This ascogenous layer has been named the ascogonium, and it 

 was at one time generally believed that it arose from a female 

 cell, the homologue of the oospore of lower fungi ; a hypha 

 which applied itself to the ascogonium was regarded as a male 

 or antheridial organ, and called a pollinodium. In other cases, 

 a thread-like hypha, which proceeded from the ascogonium, was 

 called a trichogyne; it was believed to be fertilized by means 

 of certain very small cells (spermatia) produced in special 

 structures, the spermogonia. These spermatia, though known 

 for a long time, have only recently been made to germinate, and 

 that only in nutritive solutions. The significance of the pol- 

 linodium as a male organ is not necessarily wrong, though it 

 may be a functionless structure, such as we already know 

 antheridia of many of the Phycomycetes to be. So also we may 

 still consider the spermatia as sexual bodies, even though they 

 germinate like spores, for their never-failing production before 

 aecidia would seem to suggest some relationship. In the 

 following pages we will speak of these little spores, sometimes as 

 spermatia, sometimes as conidia. 



Eeproduction of Ascomycetes may also take place by conidia 

 and chlamydospores, capable of germination to form mycelia. 



Amongst the Ascomycetes one finds the higher stages of de- 

 velopment accompanied by an almost complete enclosure of the 

 aggregations of asci. The asci of the Saccharomycetes originate at 

 any spot whatever between the mycelial threads ; in Gymnoascus 

 one finds a loose web of mycelium forming a covering to the asci ; 

 in higher forms an enclosure (sporocarp) of definite shape is 

 developed. On this account, the forms which do not produce 

 sporocarps are classed together as Gymnoasci, the sporocarpous 

 forms as Carpoasci. Amongst the latter, the sporocarp of the 

 higher forms possesses a definite opening from which the spores are 

 emitted after liberation from the asci ; certain lower forms (Peri- 

 sporiaceae) have indeed sporocarps, but these possess no opening, 

 and it is only after they have ruptured or decayed that the 

 spores are set free. 



A. Gtmnoasci. 



{Ascomycetes toithout Sporocarps.) 



The asci are produced over the whole mycelium, or from a 

 special ascogenous part of it, and are never enclosed in a sporo- 

 earp. 



