1146 



OPUNTIA 



OPUNTIA 



A. Articulations or joints strik- 



ingly different, flat to cy- 

 lindrical 1. Brasiliensis 



AA. Articulations or joints sim- 

 ilar, more or less flat- 

 tened. 



B. Species from S. America... 2. Galapageia 



3. monacantha 



4. aurantiaca 



5. crinifera 

 BB. Species from JV. America. 



c. Joints pubescent 6. microdasys 



7. basilaris 



8. puberula 

 cc. Joints not pubescent (except 



sometimes in O. pycna- 

 cantha ) . 



D. Fruit fleshy or succulent. 



E. Size of joints large: plants 



mostly large (O. crassa 

 moderately small). 

 p. Color of spines white 9. leucotricha 



10. triacantha 



11. candelabriformis 

 FP. Color of spines yellow (some- 

 times red to white in O. 

 Engelmannii, polyantha. 



crassa, and Ficus-Indica. ) 



G. Spines none or few 12. crassa 



13. Ficus-Indica 

 GG. Spines always present, few 

 to many. (One form of 

 O. macrocentra has no 

 spines, and occasional 

 plants of O. chlorotica are 

 without spines.) 14. polyantha 



15. Tuna 



16. chlorotica 



17. pycnacantha 



18. Engelmannii 

 ?FF. Color o f spines reddish 



brown to black, usually 



with purplish joints 19. phseacantha 



20. Camanchica 



21. macrocentra 



22. nigricans 

 BE. Size of joints small: joints 



variable in shape: plants 

 mostly low or prostrate. 

 (Some forms of O. Rafin- 

 esquii have moderately 

 large joints.) 23. filipendula 



24. Rafinesquii 



25. vulgaris 



26. Pes-corvi 

 DD. Fruit dry, more or less 



spiny 27. ursina 



28. hystricina 



29. Missouriensis 



30. rutila 



31. arenaria 



32. fragilis 



AA. Articulations or joints simi- 

 lar, more or less cylindri- 

 cal. 



B. Species from S. America. 

 c. Joints cylindrical, mostly 



elongated 33, 



34, 

 35, 

 36 



cc. Joints globose to broadly 

 obovate.., ...37, 



cylindrica 

 vestita 



clavarioides 

 Salmiana 



Darwinii 

 diademata 



BB. Species from N. America. 

 c. Spines without sheaths: 

 plants mostly small, with 

 clavate joints 39. pulchella 



40. clavata 



41. Grahamii 



42. Schottii 



43. Emoryi 



44. invicta 



CC. Spines sheathed: joints cy- 

 lindrical or nearly so, 

 more or less elongated. 



D. JViimber of spines variable, 



always more than one. 



E. Fruit dry, usually spiny... 45. 



46. 

 47. 

 48. 

 49. 

 .50. 

 51. 



BE. Fruit fleshy , proliferous . 



EEE. Fruit fleshy, rarely prolif- 

 erous 52. 



53. 



54. 



55. 



56. 



57. 



58. 



DD. Number of spines few, usu- 

 ally one, rarely more or 

 wanting 59. 



60. 



61. 



Davisii 



acanthocarpa 



echinocarpa 



Bernardina 



serpentina 



prolifera 



fulgida 



Bigelovii 



imbricata 



arborescens 



spinosior 



Whipplei 



versicolor 



tetracantha 



arbuscula 



leptocaulis 



ramosissima 



1. Brasili6nsis, Haw. A large, tree-like plant reach- 

 ing a height of 15-18 ft., numerously branched, with a 

 thick, roundish crown and an upright trunk, 4-6 in. in 

 diam., and bearing numerous spines 1 in. or less in 

 length: joints of two kinds, cylindrical, unarticulate, 

 elongate ones and others which are shorter and much 

 flattened and which arise as offshoots from the former; 

 the latter leaf -like, thin, 2-6 in. long, oblong, rarely ob- 

 long-lanceolate or orbicular, dark green, margin angu- 

 lar, sometimes irregular: areolse with short, gray wool 

 and numerous brown bristles; spines usually 1, some- 

 times 1-3 small additional ones, 1-2 /^ in. long, mostly 

 from the marginal areolse, white, with brownish tips : 

 fls. numerous, citron-yellow, 2 in. wide: fr. globose or 

 ellipsoidal, yellow, about 1% in. in diam. Brazil and 

 southward. One of the species most frequent in cult. 



2. Galapageia, Hemsl. An upright, tree-like plant 

 6-10 ft. high, with a circular, spreading crown and a 

 very spiny trunk, 6-8 in. in diam., and light-colored 

 bark becoming loosened and hanging in fragments 

 from the older stems: joints elliptical to oblong, thick, 

 10-14 in. long: spines at first 3-4, spreading, flexible, 

 increasing in number and size with age. finally cover- 

 ing the joints with long, brush-like bundles : fls. small, 

 less than 1 in. wide, red: fr. subglobose, red. Galapa- 

 gos Islands. 



3. monacantha, Haw. An upright plant branching 

 from the ground and reaching a height of 6 or more 

 feet: joints oblong to elliptical, rather thick, terminal 

 ones much thinner, 5-12 in. long, 3-6 in. wide, bright 

 green: areolae with uniformly short wool and yellowish 

 brown bristles; spines 1-2, seldom more, erect, %-!% 

 in. long, yellow to dark reddish brown: fls. yellow, 3 

 in. wide : fr. ellipsoidal to pyriform, occasionally pro- 

 liferous, red, somewhat spiny. Argentine Republic. 

 The horticultural variety variegata is in the trade. 



4. aurantiaca, Gill. A numerously branched, rather 

 weak, semi-prostrate plant 3-5 ft. high: joints linear- 

 lanceolate to lanceolate, 2-10 in. long, %-l in. wide, ellip- 

 tical in transverse section, dark green, turgid: areolse 

 with a tuft of grayish white wool and bright yellow 

 bristles ; spines 4-6, spreading, straight, stiff, brown 

 to yellow, the longest less than 1 in. in length : fls. yel- 

 low, l>2-2 in. wide: fr. carmine-red, globose, with short 

 spines; seed with woolly hairs. Argentine Republic. 



5. crinifera. Pfeiff. (O. senllis, Farm.). A much- 

 branched, wide-spreading plant, about 3 ft. high: joints 

 obovate to elliptical, 6 in. long and 3-4 in. wide, dark 

 green, occasionally glossy: areolse crowded, small, with 

 white wool, numerous golden yellow bristles, and a 

 variable number of long silky hairs; spines 6-8. later 

 more, white, glistening, reaching 1 in. in length, the 

 long silky hairs particularly developed on the under 

 side of the young joints fls. 3K-4 in. wide, golden 

 yellow, often reddish. Brazil(?). 



