Mamillaria similis Engelm. Pl. Lindh. 246 (1845).
Mamillaria nuttallii caespitosa Engelm. Syn. Cact. 265 (1856).
Mamillaria missouriensis caespitosa Watson, Bibl. Index,
403 (1878).
Cespitose, with 12 to 15 puberulent radial spines, the central
very often wanting, larger flowers (2.5 to 5 cm. long), fruit and
seeds (1.6 to 2.2 mm. in diameter), and 5 stigmas. (Ill. Cact.
Mex. Bound. t. 74. f 7, seeds) Type, Lindheimer, of 1845 (?) in
Herb. Mo. Bot. Gard.
From the Kansas River, Kansas, and eastern Colorado, southward
through Oklahoma to the San Antonio River, Texas.
Specimens examined: Colorado (Greene of 1870): Kansas (Carleton
551 of 1891, from Kingman County, distributed as Mamillaria
dasyacantha): Oklahoma (Carleton 120 of 1891): Texas (Lindheimer
of 1845, 1850; Wright of 1850; Reverchon 725): also specimens
cultivated in Goebel's Garden in 1846; and in St. Louis in 1846,
1847, 1851.
The cespitose masses are often a foot broad.