114 
tubercles elongated, mixed with a few stouter ones and fasciculated 
(lower ones 10 to 12 mm. long, upper ones 12 to 18 mm. long and form- 
ing an apical tuft); centrals none: flowers over 5 em. long and about 
6 to 7.5 em. in diameter when expanded, bright sulphur-yellow: fruit 
ovate and green, about 12 mm. long: seeds compressed, brownish, 
smooth and shining, 1.8 mm. long. (ll. Cact. Mex. Bound. t. A1)— 
Type unknown; that of M. pectinata Engelm. is the Wright material 
in Herb. Mo. Bot. Gard. 
Extending from the hills along the Lower Pecos to El Paso, south- 
western Texas, southward through Coahuila and San Luis Potosi to 
southern Mexico. 
Specimens examined: Texas ( Wright 226 of 1849, also of 1852; Evans 
of 1891): COAHUILA (Palmer of 1880; Mrs. Nickels): SAN Luis Povrost 
(Parry & Palmer 265; Eschanzier of 1891): also specimens cultivated 
in St. Louis in 1853; in Mo. Bot. Gard. in 1892; and in Harv. Bot. 
Gard. 
Even in the absence of the type Ihave ventured to refer Mamillaria pectinata 
Engelm, to this species, Dr, Engelmany had concluded that the two were “not 
sutliciently distinct,” and the examination of Mexican forms which pass as C. radians 
abundantly confirms this conclusion. Besides, every character in the original 
description of C. radians applies exactly to these Mexican plants and to our Texan 
specimens as well. Aside from the fact that the Mexican specimens are apt to be 
more robust, [can discover no difference whatever. For discussion of relationships 
see uniler C, scolymoides. 
46. Cactus radians pectenoides, var. nov. 
Differs in its cespitose habit, fewer (16 or 17) and stouter spines (8 to 
9inm. long), and its larger and longer (10 mm.) less deeply grooved 
tubercles.—Type in Herb. Coulter. 
San Luis Potosi. 
Specimens examined: SAN Luis Porost (Eschanzier of 1891), 
47. Cactus corniferus (DC.) Kuntze, Rev. Gen. Pl. 260 (1891). 
Mamnillaria cornifera DC. Rev. Cact. 111 (1829). 
Mamillaviaimpexicoma Lem. Hort. Monoy. Cult. 5 (1839). 
Mamillaria cornifera impexicoma Salm. Cact, Hort. Dyck. 20 (1850). 
Globose, 7.5 cm. in diameter, simple: tubercles oblong-ovate, 2 em. 
long, crowded, the younger axils woolly: radial spines 15 to 26, rigid and 
horny, curved or sometimes straight, reflexed, bulbous at base, yellow- 
ish (whiter with age) and with dark tips, very sharp, 10 to 12 mm. long; 
the central one much stouter, darker, slightly deflexed, 12 to 16 mn. 
long, sometimes wanting: flower unknown: fruit obovate, red, 2 em. 
long: seeds reddish, angular, smooth, 2 mm. long.—Type unknown. 
From San Luis Potosi to southern Mexico. 
Specimens examined: SAN Luis Porosi (Parry of 1879; Eschanzier 
of 1591): also specimens cultivated in Mo. Bot. Gard. in 1892; grow- 
ing in same garden in 1893, 
Mamillaria impexicoma Lem., vfterwards reduced toa variety, was based upon fewer 
radial spines and no central, As the central is occasionally wanting in connection 
