OPUNTIA 



the highly colored sorts are sometimes used to color 

 confectionery. 



Many of the opuntias have considerable forage value, 

 particularly during periods of long drought when other 

 forage crops are short. The range cattle of the south- 

 western United States feed on either the branches or 

 fruits, or both, of nearly all the indigenous species, the 

 flat stems of O. Engelmannii and the pendulous fruit 

 clusters of O. fulgida being most largely consumed. 

 When cattle are fed largely on unsinged native opun- 

 tias, the spines and bristles do great injury. They 

 collect mainly in the mouth, making eating very diffi- 

 cult if not impossible on this account. There are indi- 

 cations that "hairballs" composed of opuntia fibers 

 and spicules are likely to be prevalent also under such 

 conditions. 



In northern Africa the flat joints of the forms with 

 few spines are used as forage for cattle during the dry 

 season, after being allowed to ferment slightly. In 

 Tunis, plantations are sustained by dairymen for the 

 purpose of feeding their cows upon the fleshy stems. 



Species of opuntia have run wild to a remarkable extent 

 in southern Africa. They have spread rapidly during 

 the past century, and in many places have crowded out 

 the grasses and become a nuisance. Two forms of the 

 plant are recognized by the Dutch farmers; viz., a thorny 

 variety growing on the open country and on stony hill- 

 sides known as Doornblad, and a fewer-spined larger 

 variety with thicker stems known as Kaalblad. It is prob- 

 able that these two varieties originated from the same 

 introduction, for, according to Macdonald, the seed 

 from the Doornblad or Kaalblad variety may give rise 

 to plants resembling either or both of them. It is exten- 

 sively used as feed for cattle, ostriches and pigs, either 

 alone or when mixed with other forage. Here, however, 

 much harm has come from range cattle eating it in 

 times of little or no other forage, and ostriches become 

 blind from the spines and bristles getting into their 

 eyes in eating the fruits. 



In New South Wales and Australia, where several 

 species have escaped from cultivation and spread over 

 large areas of arable land and driven out more valuable 

 forage plants, the land has depreciated 50 per cent in 

 value. Here, however, some of the worthless species, 

 such as O. vulgaris and O. monacantha, are more 

 widely spread than the more valuable varieties of 0. 

 Ficus-4ndica and O. Tuna. 



From what has been said it may be seen, first, that 

 varieties of O. Ficus-indica and O. Tuna produce large 

 crops of edible and nutritious fruits; second, that plants 

 with few or no spines are the general rule in O. Ficus- 

 indica and of not infrequent occurrence in O. Tuna; 

 third, that opuntias are strong, vigorous plants that 

 will grow in situations in which few other plants will 

 thrive; fourth, that spineless forms make valuable 

 forage. 



With these and more qualities to recommend them, it 

 yet remains for horticultural enterprise to develop a 

 spineless and bristleless variety that will not only be of 

 value for forage but will produce large crops of fruits 

 as attractive to the educated palate as to the savage. 

 From the experience gained in establishing a garden of 

 nearly seventy species and varieties of opuntias, com- 

 prising about 300 plants, and watching their growth 

 and behavior for several years, it is thought that they 

 offer great possibilities in the way of improvement in 

 the hands of a careful plant-breeder. 



In recent years, the prickly pear has attracted con- 

 siderable attention as forage for cattle. Full report of 

 yields of several species in test plantations in southern 

 Texas is given in Bulletin No. 208 of the United 

 States Department of Agriculture (May, 1915) by 

 David Griffiths. See also a discussion of the forage 

 value of prickly pears by Woodward, Turner and 

 Griffiths, "Journal of Agricultural Research," August, 

 1915. 



2359 



polyantha, 14. 

 prolifera, 50. 

 puberula, 8. 

 pulchella, 39. 

 pycnantha, 17. 

 Rafinesquii, 24. 

 ramosa, 7. 

 ramosissima, 01. 

 rufida, 6. 

 rufispina, 29. 

 rutila, 30. 

 Salmiana, 36. 

 Schottii, 42. 

 senilis, 5. 

 serpentina, 49. 

 spinosior, 55. 

 splendens, 29. 

 stellata, 54. 

 stenochila, 24. 

 tessellata, 61. 

 tetracantha, 58. 

 Treleasii, 7. 

 triacantha, 10. 

 tricophora, 29. 

 tuberiformis, 32. 

 Tuna, 15. 

 ursina, 27. 

 variegata, 3. 

 versicolor, 57. 

 vestita, 34. 

 vulgaris, 25. 

 Whipplei, 56. 



KEY TO THE SPECIES. 



A. Articulations or joints strikingly dif- 

 ferent, flat to cylindrical 1. brasiliensis 



AA. Articulations or joints similar, more 



or less flattened (Nos. 2-32). 

 B. Species from S. Amer 2. galapageia 



3. monacantha 



4. aurantiaca 



5. crinifera 

 BB. Species from N. Amer. 



c. Joints pubescent 6 



7 



microdasys 



basilaris 



puberula 



leucotricha 

 triacantha 



candelabri- 



[formis 



crassa 

 Ficus-indica 



cc. Joints not pubescent (except 



sometimes in O. pycnantha). 

 D. Fr. fleshy or succulent. 



E. Size of joints large: plants 

 mostly large (O. crassa 

 moderately small). 



F. Color of spines white 9. 



10. 

 11. 



FT. Color of spines yellow 

 (sometimes red to white 

 in O. Engelmannii, O. 

 polyantha, O. crassa, 

 and O. Ficus-indica). 



Q. Spines none or few 12. 



13. 



OQ. Spines always present, 

 few to many. (One 

 form of O. macro- 

 centra has no spines, 

 and occasional plants 

 of O. chlorotica are 

 without spines.) 14. polyantha 



15. Tuna 



16. chlorotica 



17. pycnantha 



18. Engelmannii 

 FFF. Color of spines reddish 



brown to black, usually 



with purplish joints. ... 19. phseacantha 



20. Camanchica 



21. macrocentra 



22. nigricans 

 EE. Size of joints small: joints 



variable in shape: plants 

 mostly low or prostrate. 

 (Some forms of O. 

 humifusa have moderately 

 large joints.) 23. filipendula 



24. humifusa 



25. vulgaris 



26. Pes-corvi 



