OPUNTIA. 



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



Cactus ferox Nuttall, Gen. PI. i: 296. 1818. Not Willdenow. 1813. 



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



Opuntia missouriensis De Candolle, Prodr. 3: 472. 1828. 



Opunlia splcndcns Pfeiffer, Enum. Cact. 159. 1837. 



(Ipuiitiii iiiissonriensis albispina Engelmann and Bigelow, Proc. Amcr. Acad. 3: 300. 1856. 



Opuntia missouriensis microsperma Engelmann and Bigelow, Proc. Amcr. Acad. 3: 300. 1856. Not 



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

 Opunlia missouriensis philycarpa Engelmann, Proc. Amer. Acad. 3: 300. 1856. 

 Opuntiu missouriensis riijispina Engelmann and Bigelow, Proc. Amer. Acad. 3: 300. 1856. 

 Opunlia missouriensis subinermis Engelmann, Proc. Amer. Acad. 3: 300. 1856. 

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

 Opitniiti pulvacanllia borealis 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. 



199 



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 O. sphaerocarpa, where Dr. Engelmann only provisionally placed it when 

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



