Mamillaria deserti Engelm. 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.