Bui. 31, U. S. Dept. of Agriculture. 



Plate IV. 



Fig. 1.— A Plant in Its Native Habitat Upon the Highland of Mexico. 





Fig. 2.— A 5-Year-Old Plant Under Cultivation at Brownsville, Tex., Lacking 

 the Characteristic Spines so Conspicuous in Figure 1. 



opuntia tunicata. 



