ASPERGILLACEAE 



613 



on the stalk may be of considerable diagnostic value if present but must be 

 Carefully observed with high magnifications. The vesicle is partly or wholly 

 covered by a layer of cells radiating from the whole surface or parallel with 

 the long axis of the stalk if covering only the upper portion of the vesicle. 

 These cells, variously called phialides (Fig. 92, 1-3), sterigmata, or basidia, 

 may occur in either one or two layers, differentiated as primary and secondary 



Fig. 92. — Thielavia basicoln. 1, young- phialide with reserve food materials before the 

 formation of the first conidium ; 2, older stage, typical of conidial production of Chalara of the 

 Fungi Imperfect! ; 3, the left branch has formed the wall of the first conidium ; the basal cell 

 is again binucleate. The right branch shows the first conidium leaving the sheath. Thielavia 

 Sepedoniuni. i, 5, chlamydospores ; 6S, stages in copulation ; 9, ascogenous hypha with young 

 asci. (After Brierly 1915 and Emmons 1932.) 



phialides. These retain a close protoplasmic connection with the vesicle, as 

 may be seen in cases Avhere the surface of the vesicle is thickened and the 

 points of attachment of the phialides appear as pits. The length and diameter 

 and the proportion of these measurements to the diameter of the vesicle, to- 

 gether with their arrangement on the vesicular surface, furnish important 



