THE GENUS ASPERGILLUS 



383 



hyphae and conidia of several species are grey or bluish- 

 green in colour. 



The erect spore-bearing hyphae or conidiophores do 

 not branch, but end in swollen, rounded apices. The 

 sterigmata,* also, are usually simple and unbranched, 

 and bear chains of round or oval conidia (Fig. 52). 

 These fungi produce 

 small round yellow or 

 brownish perithecia or 

 fruits containing asco- 

 spores, which are more 

 frequently met with, per- 

 haps, than the corre- 

 sponding organs of Peni- 

 cillium. 



Common representa- 

 tives are : 



(i) A. glaucus, Link., 

 is a very widely distri- 

 buted fungus on old 

 bread, jam, and all kinds of decaying organic sub- 

 stances. The creeping hyphae are cottony, branched, 

 indistinctly septate : the fertile hyphae are usually 

 without septa, inflated at the end to about 60 & 

 in diameter, and covered with small sterigmata bearing 

 chains of round conidia about 8 to i o ^ in diameter. 

 The conidia are at first colourless, but later become 

 glaucous or greyish-green, and finally brownish in colour : 

 they frequently have very minute wart-like projections 

 on their outer surfaces. 



The perithecia which are commonly found on many 

 organic substrata are round, bright-yellow bodies 100 to 

 200 (j. in diameter, and containing asci with 5 to 8 



a b 



FIG. 52. Aspergillus glaucus, Link. 

 a. Conidiophores under low magnification (X 60). 

 b More highly magnified (X 300). 



