TAXONOMY 



259 



The aerial hyphae bear brush-like branches, which become con- 

 stricted on their ends into a moniliform aggregation of rounded 

 spores appearing like a row of beads. Each aerial hypha is com- 

 posed of a vertical septate branch of the mycelium called the conidio- 

 phore, branches of this, which are called secondary conidiophores, and 

 chains of spores at the tips of sterigmata (cells bearing conidia) 

 which are called conidia or conidios pores. The conidia form the 

 loose green powder characteristic of Penicillium. 





PIG. 132. Penicillium Roqueforti. a, Part of a conidiophore; b, c, other types 

 of branching; d, young conidiophore, just branching, e. f, conidiiferous cells; g, 

 h, j, diagrams of types of fructification, k, I, m, n, geminating spores. (After 

 Thorn.) 



A number of species of Penicillium are useful in the arts. Peni- 

 cillium roqueforti is the principal ripening agent of Roquefort, 

 Gorgonzola and Stilton cheeses. It possesses blue-green globular 

 conidia 4 to 5/4 in diameter. 



Penicillium camemberti is the principal agent in the ripening of 

 Camembert cheese. It possesses ellipsoidal bluish-green conidia 

 4.5 to 5.5/4 in diameter. 



