44 



A MANUAL OF THE PENICILLIA 



strains that are typically biverticillate often produce reduced conidial 

 structures, strains that are typically monoverticillate seldom develop 

 larger and more complex structures. Interpreted in this way, there is 

 for every species a general type, number, arrangement, and size of elements 

 which can be described in fairly tangible terms. Drawings and photo- 



- ->w»^ 



Fig. 8. Types of conidial structures, or penicilli. Typical monoverticillate peni- 

 cilli as seen in Penicilliuni purpurrescins (Sopp) n. comb., X 1500. 



micrographs show in detail the pattern and cellular structure that are 

 regarded as characteristic of particular species or strains. The written 

 description, however, should be broad enough to include the range of 

 patterns and dimensions that occur. It is possible to make descriptions 

 either too restrictive or too inclusive. 



For purposes of discussion, our consideration of the elements in the 

 penicillus will begin with the terminal cells (sterigmata) which bear the 



