Griffiths: Hardier Spineless Cactus 



183 



in a few species outside of the known 

 spineless forms. 



Since all of the conventional spineless 

 prickly pears are tender to frost condi- 

 tions in this country, there is no hope 

 of making decided improvement in 

 this group of plants within itself. 

 Dependence must necessarily be placed 

 in the native species of the United 

 States, which are best adapted for this 

 purpose. In the selection of our plants, 

 we must keep constantly in mind three 

 requisites; the first and foremost being 

 tonnage of production; second, resist- 

 ance to cold; and third, spinelessness. 

 Since the crop is of low nutritive value, 

 comparing with sorghum hay at a ratio 

 of 10 to 1 {i. e., 10 pounds of green 

 succulent pear equal in feeding value 

 1 pound of good sorghum hay), it is 

 absolutely essential that a comparatively 

 large tonnage be secured in order to 

 make it worth while to grow the crop. 

 Our task is so to increase resistance to 

 cold that the crop may become appli- 

 cable to a greater territory. But while 

 doing these two things, it is imperative 

 that we maintain the spineless char- 

 acter. However, we may allow our 

 notions of spinelessness to become rather 

 lax, for cattle are able to thrive on quite 

 rough feed; and absolute spinelessness 

 has never been attained in any of the 

 species thus far. All of the so-called 

 spineless species bear a few of the 

 annoying spicules; and the majority 

 of them, some spines as well. Never- 

 theless, the so-called spineless species 

 of today are sufficiently smooth for 

 cattle to eat with impunity; and we 

 can, therefore, adopt the average of 

 them as our standard of spinelessness 

 very safely. 



The conventional spineless forms meet 

 the requirements not only of spineless- 

 ness, but a number of them are suffi- 

 ciently productive as well. Our prob- 

 lem, therefore, is very much simplified 

 in that we need to increase hardiness 

 only, while maintaining, of course, the 

 other two characteristics. As stated 

 above, there is practically no hope of 

 being able to increase the hardiness 

 of these forms within themselves; for 

 they are all tender. It is, therefore, 

 necessary to look for characters outside 



of the ])rcscnt spineless species which 

 can be bred into them. The native 

 hardy species of this country — and for 

 obvious reasons it is to the species of 

 this country that we are obliged to turn 

 for hardy characteristics — are for the 

 most part spiny, and on the whole 

 unpromising. They furnish stock food 

 after being singed, but that does not 

 concern us in this study. Many of the 

 species, however, are very variable in 

 spination ; and some spiny hardy natives 

 of Texas have individuals almost if not 

 quite destitute of spines; although 

 they all have plenty of the spicules. 

 The latter, however, are also variable; 

 and individual plants may be found 

 with comparatively few of them present. 

 These are the main characteristics 

 which appear to bear upon our problem 

 of increasing the hardiness of these 

 plants; and it has been with such ideas 

 in mind that the work along this line 

 has been conducted. 



NATIVE SPECIES EXAMINED. 



For the past seven years, a constant 

 watchfulness has been exercised to 

 discover the lea.st spiny of the hardy 

 native species; and the attempt has 

 been not to go too far north for these, 

 but to work with the expectation of 

 pushing the crop, say 200 miles farther 

 north, or in other words, to increase 

 hardiness so that the species will stand, 

 we will say, temperatures of 0° F., or 

 possibly a little lower. It has been 

 considered that an attempt to make too 

 great leaps will inevitably lead to dis- 

 aster, for the species which arc hardy to 

 temperatures of 20° below zero are very 

 unpromising both from the nature of 

 their spines, and from their small 

 stature and slow growth. Our ambition 

 has been rather to produce economic 

 spineless species which will thrive in the 

 present pear region of Texas, say as 

 far north as Austin. 



Thus far, expectations have in a 

 measure been fulfilled; and three, pos- 

 sibly four or five, species have been 

 selected which are very promising for 

 further breeding purposes. It is rather 

 remarkable that in these selections, 

 field judgment has not always proven 

 reliable; for plants have not always 



