﻿542 Dodge: Effect of host on Gymnosporaxgh 



Figs. 14-19. Stages in the growth and dehiscence of a peridium; Fig. 

 ridium just appearing, very sharp pointed; Fig. 15 the same four days later s 

 It dehiscence begins at a point considerably below the apex; Fig. 16 the deh 



of wart-like galls, slightly pitted at this stage. Compare with Figs. - 



Fig. 22. Portion of the same leaf two weeks later, showing the 

 knob at .he end of each gall; one peridium well out. X 3- Compare 



in Fig. 21. The knob s 



Fig. 24. Gall with aecidium from leaf 

 ns are plainly visible although the perid 

 ve already been shed in considerable numl 



Teleutospores of Gytnnosporangium fraternu 

 vollen and the collar is distinctly visible; Fig. 

 at the apex of the upper cell; Fig. 28 germ pore 



