435 
This species is near 0. basilaris, but differs in its rounder more fleshy joints (terete 
below), pulvini not depressed (in O. basilaris there is a depression for the pulvinus 
with a furrow on either side in the general surface), yellowish bristles, and espe- 
cially in its much larger leaves. 
+ + Fruit dry and spiny: seed with very broad margin: diffuse and very spiny. 
o+ Joints compressed, suborbieular. 
49. Opuntia hystricina Engelm. Syn. Cact. 299 (1856). 
Diffuse, with obovate-orbicular compressed joints 7.5 to 12.5 cm. long: 
pulvini 10 to 12 mm. apart, with closely set yellowish or brownish 
bristles, all armed: spines 10 to 15; the upper 5 to 8 (rarely 1 to 3) 
stoutish but flexile, angular, twisted or flexuous, erect, spreading or 
deflexed, whitish or brownish, 3.5 to 10 cm, long; the lower 5 te 7 more 
slender, radiant downward, white, 8 to 18 mm. long: flowers yellow 
or purple, 5 to 7.5 em. broad: fruit obovate, with very shallow flattish 
umbilicus, 2.5 em. long: seeds irregular, black, with broad and thick 
acutish margins, 7mm. broad. (JU. Pacif. R. Rep. t. 15. f. 5-7; t. 23, f 
15)—Type, Bigelow of 1853 in Herb. Mo. Bot. Gard. 
Extending from the western side of the Rio Grande, in New Mexico, 
to southeastern California and Nevada. 
Specimens examined: NEVADA (//, Engelmann of 1859; Watson 436, 
Regan’s Valley): Arizona (Bigelow 124 of 1853; Newberry of 1858; 
Palmer of 1870, and 474 of 1890, Ft. Huachuea; Toumey of 1892, Grand 
Canyon): CALIFORNIA (Palmer 4 of 1876; Parish Bros, 163 of 1882; 
Parish of 1891; Trelease of 1892). 
This species may fairly stand as the southwestern representative of O. polyacantha, 
from which it differs in its longer and more numerous gray or reddish spines, longer 
yellow bristles, and usually smaller flowers. 
50. Opuntia polyacantha Haw. Suppl. Pl. Succ. 82 (1819). 
Cactus ferox Nutt. Gen. i, 296 (1818), not Willd. 
Opuntia media Haw. 1. ¢. 
Opuntia missouriensis DC. Prodr. iii, 472 (1828). 
Opuntia missouriensis elongata Salm, Cact. Hort. Dyck. 67 (1850). 
Opuntia missouriensis rufispina Engelm. Syn. Cact. 300 (1856), 
Prostrate, forming large spreading masses: joints light-green, orbic- 
ular, tuberculate, 5 to 10 em. (rarely 10 to 15 em.) long: leaves minute, 
3 to 4mm. long: pulvini 8 to 12 mm. apart, with reddish-brown bristles 
(fewer but longer and darker than in other forms), all armed: spines 8 
to 15; the 5 to 10 (generally 6 to 8) exterior ones radiant, setiform, 
whitish or reddish variegated; the 3 to 5 interior ones stout, reddish- 
brown (paler-tipped), 3 to 5 em, long, 2 to 4 of them deflexed, the other 
one spreading or subereet and very stout: flowers yellow (orange 
within) or sometimes purple: stigmas 5 to 8: fruit ovate, dry and spiny, 
with shallow flat umbilicus, 2.5 em. long: seeds irregular, large (5 to 6 
mm. broad). (Ul. Pacif. R. Rep. t. 14, f. 1-3)—Type unknown. 
Principally on the plains, but also in the mountains to the south, 
from the Upper Missouri and Washington to the Canadian River (Ind. 
