1919] KEMPTON—PYCNIDIUM 243 



methods, and so may be considered a combination of the two. 

 The principal method of development is meristogenous. 



Septoria scrophulariae Pk.; isolated from its host Scrophularia 

 leper ella Bicknell by Mr. Walter S. Beach during the summer of 

 1917. 



In pure culture it produces a closed sporing body, the primor- 

 dium of which arises either from a few cells of a single hypha or 

 from 2 or 3 closely lying h>phae (figs. 78, 79). These primordial 

 cells divide, swell, and continue to divide to form a small ball-like 

 structure which later develops into i or more pycnidia. They 

 thus arise either by the simple or compound meristogenous mode. 



Septoria helianthi E. and K. ; isolated from its host HeliantJms 

 grosseserratus Mortens by Mr. Walter S. Beach in the summer of 

 191 7 at Urbana, Illinois. 



Pycnidia form readily in culture. A single cell or a few adjoin- 

 ing cells in a hypha become slightly swollen. These then divide 

 into shorter cells which swell and send out very short branches 

 (fig. 80). The swelling continues until a rounded mass is formed, 

 slightly darker in color than the pale brown myceUum (fig. 81). 

 The body thus formed becomes almost globose in shape. The 

 outer portion or covering becomes membranous with a cellular 

 appearance. This primordium continues to enlarge, and becomes 

 ovate or elliptical in shape. The development is simple meristoge- 

 nous, within a single strand of mycelium. 



The genus Septoria can hardly be judged by these few species, 

 but these, with those reported in the literature, indicate that the 

 2 main methods of development, namely, meristogenous and 

 symphogenous, and even a combination of these two, may occur. 



Sphaeronaemella Karst. 



Sphaeronaemella fragariae Stevens and Peterson; procured 

 from Dr. Alvah Peterson, Urbana, IlHnois. 



A few cells of a single hypha divide, producing very short cells. 

 These bud and branch profusely, usually in one direction, into short 

 hyphae (fig. 82). These branches anastomose (fig. 83), twining 

 about in a circular manner. They then divide and swell, forming a 

 small mass which usually protrudes from one side of the main 



