OPUNTIA. 



199 



224. Opuntia polyacantha Haworth, Suppl. PI. Succ. 82. 1819. 



Cacte^/erox Nuttall, Gen. PI. i: 296. 1818. NotWilldenow. 1813. 



Opuntia media Haworth, Suppl. PI. Succ. 82. 1819. 



Opuntia missouriensis De Candolle, Prodr. 3: 472. 1S28. 



Opuntia splendens Pfeiffer, Enum. Cact. 159. 1837. 



Opuntia missouriensis albispina Engelmann and Bigelow, Proc. Amer. Acad. 3: 300, 



Opuntia missouriensis microsperma Engelmann and Bigelow, Proc. Amer. Acad. 3: 300. 



0. rafinesquei microsperma Engelmann, Proc. Amer. Acad. 3: 295. 1856. 

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

 Opuntia missouriensis rufispina Engelmann and Bigelow, Proc. Amer. Acad. 3: 300. 

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

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

 Opuntia polyacantha borcalis Coulter, Contr. U. S. Nat. Herb. 3: 436. 1896. 

 Opuntia polyacantha platycarpa Coulter, Contr. U. S. Nat. Herb. 3: 436. 1896. 

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

 Opuntia schweriniana Schumann, Monatsschr. Kakteenk. 9: 148. 1899. 



1856. Not 



1S56. 



Fig. 247. — Opuntia polyacantha. 



Low, spreading plants, with fibrous roots, usually forming small clumps; joints not very thick, 

 orbicular, usually less than 10 cm. in diameter, generally light green; areoles small, closely set, 

 usually less than i cm. apart, all spiny; spines numerous, often 9, those from the sides mostly short, 

 appressed, and white, but often i or 2 of these elongated and like those from the upper and marginal 

 areoles, dark brown, with lighter tips and about 3 cm. long; glochids yellow; flowers small, 4 to 5 cm. 

 long, including the ovary; sepals tinged with red; petals lemon-yellow; stigma-lobes green; fruit 

 dry, oblong, 2 cm. long, bearing small clusters of white, acicular spines at the areoles; seeds white, 

 6 mm. long, acute on the margin. 



Type locality: Arid situations on the plains of the Missouri. 



Distribution: North Dakota to Nebraska, Texas, and Arizona to Utah, Washington, 

 and Alberta. 



Opuntia sphaerocarpa utahensis Engelmann (Trans. St. Louis Acad. 2: 199. 1863) can 

 not be referred to 0. sphaerocarpa, where Dr. Engelmann only provisionally placed it when 

 he first described it. On account of its yellow flowers we have referred it here. Opuntia 



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