OPUNTIA. 



145 



back from the Southwest by W. H. Emory. They can never be critically identified, but 

 are probably of this relationship. 



Illustrations: Bngler and Prantl, Pflanzenfam. 3^'':f. 57, C; Forster, Handb. Cact. ed. 

 2. f. 141; Illustr. Fl. 2:f. 2530; ed. 2. 2:f. 2989; Pac. R. Rep. 4: pi. 9, f. i to 5; pi. 22, f. 



Wiener Illustr. Gartenz. 10: f. 115, all as Opuntia camanchica; N. Mex. Agr. E 



Sta 



Herb. 12 : pi. 55, as Opuntia blakeana; Cact. Mex 



pi. 75, f. 9 to 13. . . . . ^ , 



Plate XXV, figure 2, represents a flowermg jomt of a 



from Tucson, Arizona, in 191 6, by 



Mac 



plant sent 

 Dougal. 



146. Opuntia mojavensis Engelmann, Proc. Amer. Acad. 3: 293. 



1856. 



Prostrate, with suborbicular joints ; pulvini remote, with large 

 yellow bristles; spines 2 to 6, stout and annulate, acutely angu- 

 lar and compressed, more or less curved, reddish brown, paler 

 toward tip, 2.5 to 6 cm. long, i to 3 smaller, slenderer, pale ones 

 added below; fruit oblong, 4.5 cm. long. 



Moj 



west of the Colorado, 



California. 



Distribution: Known only 



Fig. 183. — Opuntia covillei. X0.4. 



from 



m 



men has been examined ; we have 

 been unable to refer any other 

 specimens to this species, which 

 is thus very imperfectly under- 

 stood. 



Illustration: Pac. R. Rep. 4'- 



pi. 9, f. 6 to 8. 



147. Opuntia covillei Britton and 



Misc 



532. 1908. 



Opuntia megacarpa Griffiths, 

 Rep. Mo. Bot. Gard. 20: 

 91. 1909. 



Opuntia rugosa Griffiths, Proc. 

 Biol. Soc. Washington 27: 



27. 1914- 



Bushy plants, usually growing 

 in dense thickets; joints orbicular to 

 obovate, 10 to 20 cm. long or more, 

 pale green, sometimes purplish, 

 slightly glaucous; areoles 2 to 4 cm. 

 apart ; spines several from an areole, 

 slender, unequal, the longest ones 

 6 cm. long, white when young, 

 brownish when old; flowers large, 

 yellow. 



Type locality: San Bernard- 

 ino, California. 



Distribution: Interior valleys 



of southern California. 



,g^._Opuntia covillei. 



Opuntia covillei and O. 



V 



grow in the same 



When growing 



may 



'. J 



