Mamillaria vivipara radiosa neo-mexicanaEngelm. 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 theWright, 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 arizonicaEngelm 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 to30 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 of1853; 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.

61.Cactus radiosus deserti(Engelm.).

Mamillaria desertiEngelm. Bot. Calif. ii. 449 (1880).

Subglobose or oval (5 to 10 cm. high) and simple, with deeply grooved tubercles (slender and about 12 mm. long), 25 to 30 rather long(10 to 16 mm.) grayish white radial spines (the larger with reddish tips), 3 or 4 shorter and stouter centrals with 5 or 6 intermediate ones above, small (2.5 cm. long) straw-colored flowers (becoming purplish-tipped), 5 or 6 stigmas, and obliquely obovate curved seeds.Type, Parish 433 in Herb. Mo. Bot. Gard.

In the mountains bordering the deserts of southeastern California (San Bernardino County) and extending to central Nevada (Reese River Valley).

Specimens examined: California (Parish 453 of 1880, also of 1882; Bailey of 1890): Nevada, Lincoln County (Coville & Funston of 1891, Death Valley Expedition): also specimens cultivated in Meehan's Gard. in 1882.

The smaller straw-colored flowers alone suggest the propriety of keeping this form specifically distinct, but even in size and color there is an occasional tendency toward the specific character.The obliquely obovate curved seeds resemble those of C. viviparus.The plant densely covered with stout ashy-gray interlocking spines is easily recognized.

62.Cactus radiosus chloranthus(Engelm.).

Mamillaria chloranthaEngelm. Wheeler's Rep. 127 (1878).