Mamillaria vivipara radiosa neo-mexicana Engelm. Syn. Cact. 269 (1856).
Generally lower (3.5 to 10 cm.) and subglobose to ovate or even sub-cylindrical, branching at base or simple, with more numerous (12 to 40) radial spines, more numerous (3 to 12) and purplish centrals, and smaller seeds. (Ill. Cact. Mex. Bound. t. 74. fig. 4, seeds) Type, presumably the Wright, Bigelow, and Schott specimens from western Texas, New Mexico, and Sonora, all in Herb. Mo. Bot. Gard.
From southern Utah, central Colorado, and western Kansas, southward through western Texas, New Mexico and Arizona into Chihuahua and Sonora.
Specimens examined: Kansas (Carleton 530 of 1891, in Meade
County): Oklahoma (Carleton 233 of 1891): Colorado (Hall and
Harbour of 1862; Brandegee 645 of 1873; Hicks of 1890): Utah
(Siler of 1870): New Mexico (Wislizenus of 1846; Fendler 244,
271, of 1847: Wright 298; Bigelow of 1853; G. R. Vasey of 1881):
Texas (Wright of 1849, 1851, 1852; Bigelow of 1853): Arizona
(Rothrock, with no number or date): Sonora (Schott of 1855):
Chihuahua (Evans of 1891, near Juarez).
It is through this variety that C. radiosus approaches most nearly to C. viviparus, in the forms with few radials and centrals, but the specific characters seem to hold. This is the Mamillaria vivipara of the Syn Fl. Colorado (Porter and Coulter).
60. Cactus radiosus arizonicus (Engelm.).
Mamillaria arizonica Engelm Bot. Calif. i. 244 (1876).
A robust globose or ovate simple form (7.5 to 10 cm. in diameter), with long (12 to 25 mm.) deeply-grooved tubercles, 15 to 20 long (10 to 30 mm.) rigid whitish radial spines, and 3 to 6 centrals deep brown above. Type, the specimens of Cous, Palmer, Bischoff and Johnson, all in Herb. Mo. Bot. Gard.
Sandy and rocky soil from southern Utah through northern and western Arizona to southern California.
Specimens examined: Arizona (Cous of 1865; Cous & Palmer of 1865 and 1872; Palmer of 1869; Bischoff of 1871; Miller of 1881; Rusby 617 of 1853; Pringle of 1884): Utah (Johnson of 1871, 1872, 1874; Parry of 1875, 1877): California (Parish of 1880): also specimens cultivated in Mo. Bot. Gard. in 1881; and in Meehan's Gard. in 1882.