OBSERVATION AND DESCRIPTION OF PENICILLIA 



47 



of a short basal tube narrowed to a long neck which is characteristically 

 bent from the main axis of the sterigma (fig. IID). 



The first sterigma in a verticil is a terminal cell which becomes trans- 

 formed into a spore producing organ, the second pushes out from the cell 

 below at the base of the first, and successive sterigmata bud out to form a 

 whorl, verticil or cluster, on the apex of the main axis or some secondary 

 branch thereof. The apex may be unchanged in size or variously enlarged 

 toward the appearance and proportions of the vesicle of a small Aspergillus. 

 The number of sterigmata in the verticil may be few and readily deter- 

 minable, or suflficiently large to render determination entirely impractic- 



FiG. 11. Sterigmata of different types. A, Penicillium expanswn hink, showing 

 sterigmata of the type developed in most species of Penicillium. B, P. janthinellum 

 Biourge, showing a type of sterigma with conspicuously narrowed conidium bearing 

 tul)e thatis characteristic of the P. ja?ii/!2rteZZam series and certain other species includ- 

 ing ascosporic members of the Monoverticillata. C, P. funiculosum Thom, showing 

 lanceolate sterigmata of the type characteristic of the Biverticillata-Symmetrica. 

 D, Paecilomyces varioti Rainier, showing characteristic long-tapering sterigmata 

 with tips often bent away from the main axes of the sterigmata. Camera lucida 

 drawings, X 1500. 



able. In any case, and contrarj^ to the figures of some early workers, 

 absolute regularity of parts is seldom if ever observed. 



Melulae 



The cells bearing the sterigmata in biverticillate forms are known 

 as metulae (fig. 7B) . These are characteristically borne in a terminal 

 verticil on the main axis of the conidiophore, or on the main axis and one 

 or more branches from it. If we accept the sterigma as the primary coni- 

 dium-producing organ, the term metula may properly be restricted to 

 apply to the characteristically differentiated members of the second series 

 of branches, each supporting a group or verticil of sterigmata. They have 



