156 



POLYGONE^E 



PLATE I. 



FIG. i. Cross-section of Canaigre root (Rumex 

 kymenosepalus). X Stt- (Photomicrograph.) 



FIG. 2. Cross-section of Chinese Rhubarb. 

 (Photomicrograph.) 



FIG. 3 .Cross-section of Rheum rhaponticum. Xs5^- (Photomicrograph.) 



