PLATE 88 
A. —Cross section of a petiole of Ribes roezli, showing the pericycle (a) and pith ( b ) 
regions which are stuffed with the mycelium of Cronartium ribicola . Most of the 
pith cells have been destroyed. Teliospores partially fill the cavity. 
B. —Longitudinal section of the same petiole, showing the manner in which the 
sori force aside the parenchyma cells of the pith. 
C. —Internal telium of Cronartium ribicola from the pericycle region of a petiole of 
Ribes roezli. The telium has been forced to coil on account of the pressure of the 
surrounding cells. 
D. —Internal telium of Cronartium ribicola from the pericycle region of a petiole of 
Ribes roezli flattened by pressure. 
E. —Young internal telium of Cronartium ribicola from the center of the pith region 
cf a petiole of Ribes roezli , illustrating the depth at which sori may start to develop. 
