144 "^he; cactaceae;. 



145. Opuntia phaeacantha Engelmann in Gray, Mem. Amer. Acad. 4: 52. 1849. 



Opuntia phaeacantha brunnea Engelmann, Proc. Amer. Acad. 3: 293. 1856. 

 Opuntia phaeacantha major Engelmann, Proc. Amer. Acad. 3: 293. 1856. 

 Opuntia phaeacantha nigricans Engelmann, Proc. Amer. Acad. 3 : 293. 1 856. 

 Opuntia camanchica Engelmann and Bigelow, Proc. Amer. Acad. 3: 293. 1856. 

 Opuntia chihuahuensis Rose, Contr. U. S. Nat. Herb. 12: 291. 1909. 

 Opuntia toumeyi Rose, Contr. U. S. Nat. Herb. 12: 402. 1909. 

 Opuntia blakeana Rose, Contr. U. S. Nat. Herb. 12: 402. 1909. 

 Opuntia zuniensis Griffiths, Bull. Torr. Club 43: 86. 1916. (From the description.) 



Low, usually prostrate, with some branches ascending; joints usually longer than broad, 10 to 

 15 cm. long; areoles rather remote, the lower ones often spineless; spines i to 4, those on the 

 sides of the joints more or less reflexed, somewhat flattened, usually rather stout, brown, some- 

 times darker at base, or often nearly white throughout, the longer ones 5 to 6 cm. long; glo- 

 chids numerous, yellow to brown; flowers 5 cm. broad, yellow; ovary short; fruit 30 to 35 mm. 

 long, much contracted at base. 



Type locality: About Santa Fe and on the Rio Grande, New Mexico. 



Distribution: Texas to Arizona and Chihuahua. 



We have referred to Opuntia phaeacantha the common low, bushy Opuntia with small 

 joints, brown spines, and yellow flowers of the Southwest ; we formerly regarded it as com- 

 posed of several species, and others have followed our lead ; but we are unable to draw any 

 distinct Hnes after a study of much additional herbarium and greenhouse material. Dr. 

 Rose has collected a large series of specimens from the Southwest, especially from the type 

 localities, but his specimens seem to bridge over differences which before seemed tangible; 

 cited differences appear to be racial rather than specific. 



Opuntia blakeana, which is found west of the Rocky Mountains, one would expect to 

 be different. It is characterized by small obovate joints, rather short spines, small yellow 

 flowers purple at center. 



Opuntia chihuahuensis, which was first described from Mexican specimens, if it belongs 

 here, is in the southern range of 0. phaeacantha. It, too, has yellow flowers with red 

 centers, rather large joints, and long, slender spines. Mr. Wooton is of the opinion that to 

 O. chihuahuensis is to be referred the common, low, brown species from El Paso, which 

 includes the specimens of G. R. Vasey, which Coulter called Opuntia mesacantha oplocarpa. 

 This long-spined form extends north throughout eastern New Mexico to southeastern 

 Colorado. With the latter form Mr. Wooton believes Opuntia camanchica belongs. If 

 we take this broad view of the limits of this species we are forced to include Opuntia 

 toumeyi, although it is much larger than 0. blakeana, and was considered by Dr. Rose to 

 be different. 



Opuntia mesacantha sphaerocarpa Wooton and Standley (Contr. U. S. Nat. Herb. 19: 

 446. 19 15) is a mistake, 0. mesacantha oplocarpa being intended. 



Opuntia rubrifolia Engelmann in Coulter (Contr. U. S. Nat. Herb. 3: 424. 1896), 

 from St. George, Utah, belongs in this series if E- W. Nelson's No. 156, from the same place 

 has been properly determined as such. The type specimen of 0. rubrifolia has, apparently, 

 been lost. 



The following varieties of Opuntia camanchica have been offered by Haage and Schmidt 

 in their catalogues: albispina (Trade Seed Cat. 104. 1911-1912); orbicularis, rubra, and 

 salmonea (all in Haupt-Verzeichnis 1908: 228. 1908). Under 0. camanchica has been 

 mentioned also variety luteo-staminea (Cat. Darrah Succ. Manchester 53. 1908). 



Opuntia eocarpa Griffiths (Proc. Biol. Soc. Washington 29: 11. 1916), also 0. recurvo- 

 spina Griffiths (Proc. Biol. Soc. Washington 29: 12. 1916) and possibly 0. superbospina 

 Griffiths (Proc. Biol. Soc. Washington 29: 13. 191 6) and 0. caesia Griffiths (Proc. Biol. 

 Soc. Washington 29: 13. 1916) are of this relationship. 



Opuntia microcarpa* Engelmann (Emory, Mil. Reconn. 158. f. 7. 1848) and 0. violacea 

 Engelmann (Emory, Mil. Reconn. 158. f. 8. 1848) were described from drawings brought 



*Since the above was written Dr. Griffiths (Bull. Torr. Club, 43: 527) has pubHshed a detailed account of this 

 species, which he regards as distinct; it inhabits southern Arizona. 



