PLATE 12 
Stages in the development of Sclerotinia ricini. 
A. —Portion of mature head of Botrytis stage. Note dichotomous branching. 
B. —Germinating conidia. 
C. —Immature conidia, showing attachment to conidiophore. 
D. —Base of a conidiophore, hyaline and vacuolate, gradually becoming olivaceous 
above the substratum. 
E. —Asci, ascospores, and paraphysis. 
F. —Microconidium production on vegetative hyphae. 
G. —The same on germinating ascospores. 
H. I.—Stages in germination of two of the ascospores which gave two of the original 
single ascospore cultures. 
Drawings made with the camera lucida. Magnification is indicated by the scales, 
one space of which, in each case, represents io n. 
27134—23 - 4 
