EUROTIUM ASPERGILLUS. 119 



Some observers look on this supposed sexual copulation 

 as only an unimportant anastomosis of hyphae. 



Besides the perithecia many perisporiacese present a 

 second asexual fructification on the same mycelium ; 

 simple fruit hyphae are formed which give rise to spores, 

 or conidia, by fission. This asexual fructification is 

 extremely widely spread, and very frequently it is the 

 only form ; it is only the presence of a large amount of 

 nutriment which predisposes to the formation of peri- 

 thecia. Thus the most common mould fungi usually 

 form only the asexual fructification, and their connection 

 with the perithecial forms is for the most part only 

 recognised at a later period. Hence the conidia forms 

 of these fungi were described as particular species, while 

 from recent researches they can only be looked on as 

 secondary fructifying forms of the ascomycetes. The 

 conidia germinate readily immediately after they are ripe, 

 form a mycelium, and again develop conidia bearers ; 

 on mycelium arising in this way from conidia, peri- 

 thecia can also presumably develop under suitable con- 

 ditions, but this has not as yet been directly observed. 

 The ascospores are as a rule only -able to germinate 

 after a period of rest ; in the case of some of them it is 

 certain that they develop to form a conidia-bearing 

 mycelium. The most important species are 



Euroliumafpcrgillus. 



We distinguish (after Siebenmann) the so-called true Aspergillus. 

 aspergilli (Asp. clavatus, fiavus, fumigatus, niger, 

 ochraceus, albus), and the two eurotium forms proper 

 (Eurotium aspergillus glaucus and Eurotium repens). 

 In the former the higher form of fructification is repre- 

 sented by a form of sclerotium, the formation of which 

 is completed in two periods. In the first period a rest- 

 ing fruit (Dauerfrucht) is formed consisting of the 

 centrally placed ascogonium, which is for the time 

 being inactive, and the store material originating from > 

 the carpogonium. This condition persists so long as 

 the sclerotium is in a dry surrounding. On a moist 



