18 



A MANUAL OF THE ASPERGILLI 



Thickening of the conidiophore wall may be uniform or may be greater 

 at the base, thinning to negligible toward the apex. Two general sections 



Fig. 2. Development of the conidial apparatus in Aspergillus niger. A, Foot 

 cell bearing young conidiophore as a vertical branch. B, Developing conidiophore, 

 X 172. C and D, Development of the vesicle by swelling of the terminal portion of 

 the conidiophore, X 265. E x and E*, Vesicle in optical section and surface view 

 showing early development of primary sterigmata, X 265. F , Later stage in develop- 

 ment of primary sterigmata, X 265. _G, Young fruiting head showing secondary 

 sterigmata bearing chains of conidia, X 265. 



based upon the character of the thickening of the conidiophore wall are 

 fairly readily distinguished, although the careful use of high magnification 

 is occasionally necessary to separate certain strains. In the first, the 



