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



Plate III. 



Fig. 1.— A Nearly Spineless Species of Opuntia (0. cacanapa), Native of the 

 Laredo Region of Texas, as Grown at San Antonio. 



Fig. 2.— An Arizona Desert Species of Opuntia (O. discata) Under Cultivation 

 at San Antonio, Showing Its Changed Habit Under Changed Conditions. 



The large size of the joints and the reclining nature of the main limbs are conspicuous modifi- 

 cations due to changed conditions. 



OPUNTIA CACANAPA AND OPUNTIA DISCATA. 



