121 
60. Cactus radiosus arizonicus (Engelm.). 
Mamillaria arizonica Engelm. Bot. Calif. i. 244 (1876), 
A robust globose or ovate simple form (7.5 to 10 em. 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.—Ty pe, the specimens of Cous, Palmer, Bischoff, and J ohnson, 
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 1883; Pringle of 1884): Uran (Johnson of 1871, 1872, 1874; 
Parry of 1875, 1877): CALIFORNIA (Parish of 1880): also specimens cul- 
tivated in Mo. Bot. Gard. in 1881; and in Meehan’s Gard. in 1882. 
61. Cactus radiosus deserti (Engelm.). 
Mamillaria deserti Engelm. Bot. Calif. ii. 449 (1880). 
Subglobose or oval (5 to 10 em, high) and simple, with deeply grooved 
tubercles (slender and about 12 mm. long), 25 to 30 rather long (10 to 
16mm.) 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 453 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): Nuevapa, 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 chlorantha Engelm. Wheeler’s Rep. 127 (1878). 
Oval to cylindrical (7.5 em. in diameter, sometimes 20 to 22.5 em. 
high), with 20 to 25 gray radial spines almost in two series, 6 to 9 
stouter reddish or brownish-tipped centrals (12 to 25 mm. long), and 
yellowish or greenish-yellow flowers 3.5 em. long and wide.—Type: 
Southern Utah specimens of both Parry and Johnson occur in Herb. 
Mo. Bot, Gard., but they are all referred to C. radiosus arizonicus, and 
I can find no trace of any specimens of O. radiosus chloranthus in the 
Engelmann collection. 
Southern Utah, east of St. George (Parry; Johnson), 
