OPUNTIA. 



195 



Illustration: Cact. Mex. Bound, pi. 75, f. 15. 



Figure 240 is from a drawing of the plant collected by Dr. Rose near El Paso, Texas, in 



1913- 



218. Opuntia trichophora (Engelmann) Britton and Rose, Smiths. Misc. Coll. 50: 535. 1908. 



Opuntia missouriensis trichophora Engelmann, Proc. Amer. Acad. 3: 300. 1856. 

 Opuntia polyacantha trichophora Coulter, Contr. U. S. Nat. Herb. 3: 437. 1896. 



A low, spreading plant, often forming small clumps 6 to 10 dm. in diameter; joints orbicular 

 to obovate, 6 to 10 cm. in diameter; areoles closely set; spines numerous, very unequal, the longer 

 one 4 cm. long or so, acicular, pale, often white, but on old joints developing into long, weak hair- 

 like bristles; flowers yellow, the sepals tinged with red; ovary with numerous areoles, these bear- 

 ing weak, pale bristles; fruit unknown. 



Type locality: Mountains near Albuquerque, New 

 Mexico. 



Distribution: New Mexico, Texas, and Oklahoma. 



This plant, while closely related to Opuntia polya- 

 cantha, seems worthy of specific rank, its long weak spines 

 being apparently characteristic. Its northern extension 

 into Oklahoma has recently been determined 

 from plants collected by G. W. Stevens. 



Illustrations: Pac. R. Rep. 4: pi. 15, f. i 

 to 4; pi. 23, f. 19, all as Opuntia missouriensis 

 trichophora. 



Figure 241 is copied from the first illus- 

 tration above cited. 



KiG. 240. — Opuntia arenaria. X0.75. 



Fig. 241. — Opuntia trichopho 



219. Opuntia erinacea Engelmann, Proc. Amer. Acad. 3: 301. 1856. 



Opimlia ursina Weber, Diet. Hort. Bois 896. 1898. 



Growing in small, low clumps, the branches ascending or erect; joints ovate to oblong, flattened 

 or thick, sometimes nearly terete, 8 to 12 cm. long; areoles somewhat tuberculate, large, numerous, 

 closely set, 4 to 10 mm. apart; spines numerous, usually white or sometimes brownish or with brown 

 tips, slender, often 5 cm., sometimes 12 cm. long or even more, stiff, often developing on the old 

 joints as long hairs or bristles; glochids numerous; flowers rather large, 6 to 7 cm. long, either red or 

 yellow; ovary and fruit very spiny; seeds large, rather regular. 



Type locality: On Mojave Creek, California. 



Distribution: Northwestern Arizona, southern Utah, southern Nevada, and eastern 

 California. 



