114 LUTHER BURBANK 



names, as Tuna Amarillo, Tuna Colorado, Tuna 

 Blanca, etc. 



Another quite common Mexican form known 

 as Tapuna appears to be entitled to recognition 

 as a distinct species of Opuntia. 



It produces flat leaves that are generally 

 circular or heart-shaped. The plant does not 

 grow as rapidly as others of the large-fruit 

 Opuntias, and the fruit ripens late in the season. 

 The leaves have a somewhat white appearance, 

 as if dusted with flour, which distinguishes them 

 very readily from the others. The fruit is rarely 

 edible except for stock. 



The Tapuna is also of rather exceptional com- 

 pactness of growth and has high nutritional 

 value as a forage plant. Moreover it is a much 

 hardier species than many others, resisting both 

 cold and wet better than most of the best 

 Opuntias. 



So this species has characteristics of obvious 

 value from the standpoint of the plant developer. 



THE QUESTION OF SPINELESSNESS 



But what about the matter of spines? 



This, of course, from the standpoint of the 

 present investigation, is the vital question. 



The question might be answered categorically, 

 with the statement that not a single one of the 



