BULLETIN 31, U. S. DEPARTMENT OF AGRICULTURE. 



species from the immediate vicinity of Brownsville have been em- 

 ployed in our economic plantings, because it was early recognized 

 that these were the best adapted to the conditions and would make 

 the largest tonnage of any that could be grown. 



All species of this region are exceedingly spiny. They are even 

 more spiny than those of the San Antonio region; moreover, the 

 spines remain green for a longer period and are consequently much 

 more difficult to singe properly preparatory to being fed. This is a 

 serious economic consideration and one which is difficult to pre- 

 vent. Under the humid conditions of the coastal region the tendency 



is for the spines (fig. 

 1, a) and the spicules 

 (fig. 1, b) of all spe- 

 cies to become dry 

 much more slowly 

 than in the more arid 

 atmosphere of the re- 

 gions farther inland. 

 In the cultivation of 

 this crop it is there- 

 fore necessary for one 

 to choose between the 

 spineless forms not 

 needing singeing and 

 the much more pro- 

 ductive spiny native 

 varieties, which are 

 not only difficult but 

 often impossible to 

 singe properly. It 

 may be possible in 

 time to breed varieties 

 better adapted than 

 the native ones, but the development of such forms from the spiny 

 native prickly pears of the delta of the Rio Grande is an almost 

 hopeless task, the variation in the number of spines produced being 

 so trifling as to scarcel}' warrant selection, while they do not appear 

 to hybridize readily with the spineless forms. 



In June, 1905, the Office of Foreign Seed and Plant Introduction 

 of this Bureau received from Dr. G. Borg, San Giovanni, Island 

 of Malta, a few cuttings of a large spineless species, to which was 

 assigned S. P. I. No. 14807. The plant passes in both this country 

 and the Mediterranean region as spineless. About half a dozen 

 cuttings of this importation were planted and grew for two and 



Fig. 1. — A pulvinus, or cushion of spines (a) and spic- 

 ules (&), from the edge of a joint of Opuntia lind- 

 heimeri from the San Antonio region of Texas. 



