536 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vol. 50 



Engelmann's from the Mohave River. We think it possible that 

 Dr. Engelmann erred in this identification and that O. rutila really 

 belongs among the Xerocarpeae. 



OPUNTIA ARENARIA Engelm. 

 Opuntia arenaria Engelm. Proc. Am. Acad. 3:301. 1856. 



Type locality : Sandy bottoms of the Rio Grande near El Paso. 

 Distribution : Texas and New Mexico. 

 Illustration : Cact. Mex. Bound, pi 75. fig. 1$. 



OPUNTIA FRAGILIS (Nutt.) Haw. 



Cactus fragilis NuTT. Gen. 1:296. 1818. 



Opuntia fragilis Haw. Syn. PI. Succ. Suppl. 82. 1819. 



Type locality : ''From the Mandans to the mountains, in sterile but 

 moist situations." 



Distribution : Wisconsin to Kansas and British Columbia. 



Illustrations : Pac. R. Rep. 4 : pi. 24. fig. 5; 111. Fl. fig. 2532; W. 

 Watson, Cact. Cult. fig. 78. 



OPUNTIA BRACHYARTHRA Engelm. 



Opuntia brachyarthra Engelm. Proc. Am. Acad. 3:302. 1856. 

 Opuntia fragilis brachyarthra CoulT. Contr. Nat. Herb. 3:440. 1896. 



Type locality : Inscription Rock, near Zuni, New Mexico. 

 Distribution : Colorado and New Mexico. 



Illustrations : Forst. Handb. Cact. ed. 2. fig. 132; Cact. Journ. 

 1 : 100. 



Series ALBISPINOSAE 



Tall or large plants with white spines and broad petals. 



OPUNTIA OLIGACANTHA Salm-Dyck 



Opuntia oligacantha Salm-Dyck, Cact. Hort. Dyck. 241. 1850. 



Type locality : Not cited ; cultivated in the Vienna garden. 

 Distribution : Mexico. 



OPUNTIA HYPTIACANTHA Weber 



Opuntia hyptiacantha Weber in Bois, Diet. Hort. 894. 1897. 



Type locality : Mexico. 

 Distribution : Mexico. 



