PLATE i 
A. —Young castor bean inflorescence recently infected with Sclerotinia ricini. Note 
the center of infection with heavy production of gray mold, the very recently infected 
spots exuding amber-colored drops of liquid, and the variation in stage of development 
of the flowers, both male and female. 
B. —Portion of the stalk of a castor bean plant with sclerotia, developed in the sub¬ 
cortical layers, appearing at the surface. 
C. —Axis of an old diseased inflorescence, with the pods long since fallen. Note the 
sclerotia developing at the base. 
D. —Apothecia and sclerotia of 5 . ricini. 
Reproduced from painting by J. Marion Shull. 
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