Griffiths: Hardier Spineless Cactus 



187 



napa." It makes no difference whether 

 it is the form with the single erect spine, 

 the smooth, or the exceedingly spiny 

 one that he is dealing with. Sometimes 

 he will apply a qualifying adjective to 

 designate the different forms. But 

 they are all "cacanapa" to him. 



The artist has brought out the differ- 

 ence in fig. 15, so that little further 

 need be said. It may be added, how- 

 ever, that the differences in what we 

 consider varieties in this species are 

 greater than those used to distinguish 

 species in other groups. The differences 

 are not confined to spines alone; in 

 varying degrees, they are those of the 

 entire range of characters used for 

 taxonomic purposes. The species is 

 typically glaucous ; but many individuals 

 are yellowish-green, and it is in the 

 yellowish-green varieties that the great- 

 est spination occurs. Typically, the 

 joints are subeircular; but there is 

 little regularity in shape, except in so 

 far as the individual or groups of 

 individual plants are concerned. There 

 is, however, a striking similarity in the 

 fruit of the entire group of varieties, 

 a similarity possessed by this and one 

 or two other species. 



In the illustrations are shown differ- 

 ences in spination mainly, that being 

 the most striking variation. With these 

 spiny forms is to be compared the 

 spineless, but not spiculeless, variety 

 shown in fig. 15. There are but few 

 species in southern Texas more spiny 

 than Op. cacanapa; and likewise, no 

 native species with fewer spines. There 

 are other species which from some stand- 

 points are more promising for breeding 

 purposes in this pear region; but their 

 constant spininess renders them unfit. 

 This is simply another instance of the 

 oft-repeated principle that those plants 

 and those only are favorable objects 

 for selection which have great range of 

 variation. 



Our experience with these plants 

 leads us to think that there are no 

 species more promising for increasing 

 the hardiness of the spineless prickly 

 pears than Opuntia cacanapa, Op. ellis- 

 iana, and Op. subarmata. To these may 

 be added Opuntia bentonii; two or three 

 other varieties rather closely related to 



Op. subarmata; and one apparently 

 entirely without spines, but having 

 spicules in about the same proportion as 

 typical Op. bentonii. At present this is 

 thought to be a variant of Op. bentonii. 

 Since breeding work with these species 

 is already well under way, it is desirable 

 to have the forms we are using charac- 

 terized and fixed in type as accurately 

 as may be for purposes of later com- 

 parison as well as to record the facts 

 of the selection of such rare plants 

 among an abundance of very spiny 

 species on the one hand, and on the 

 other, very spiny individuals of the 

 same species. It is very probable 

 that the conventional tender spineless 

 forms owe their origin to much the 

 same process of selection as here 

 employed; but it has continued through 

 many generations of time. Some of 

 it has been conscious and some uncon- 

 scious; some of it American and some 

 European. 



Opuntia c.\c.\napa Griffiths. 



An erect or ascending, spreading, open- 

 branched species, reaching a height of 13^- 

 2 m., and a spread of branch of 13^-23^ m.; 

 joints subeircular, about 16 x 18 cm., glaucous, 

 gray-green, when mature, but turning more 

 yellowish by loss of bloom in age; areoles 

 white when young, turning tawny at maturity, 

 and dirty gray in age, subeircular to broadly 

 obovate, 3 mm. long on edge, smaller on sides 

 of joints, becoming subeircular and somewhat 

 larger when old; leaves long, prominent, oval 

 in section, arising from an abrupt small 

 tubercle, 1 mm. high, 16-17 mm. long, subulate, 

 cuspidate, broadly arched backwards; spicules 

 light yellow, unequal, scattered through entire 

 edge of areole, but more prominent above, 

 with the wool in the center and 1 or 2 mm. 

 high on edges of joints, 3-5 mm. long, but 

 much shorter on sides; spines almost absent; 

 only an occasional one in a rare areole 1 or 2 

 cm. long, seldom seen; flowers deep yellow, 

 about 7 cm. in diameter when open, and petals 

 5 cm. long, filaments yellow above, greenish 

 tinged at base, style white, stigma white, 

 8-parted with long linear divisions; fruit red 

 throughout, small, obovate to subglobose, 

 3-43^ cm. in diameter with comparatively 

 thick rind. 



This variety of Opuntia cacanapa is of 

 medium rapid growth, somewhat slower 

 than Opuntia lindheimeri of the San 

 Antonio region. In structure it is 

 somewhat more fibrous, and the joints 

 are not so thick. This is characteristic 

 of all of the varieties of this species. 



