Mamillaria lasiacantha denudata Engelm. Cact. Mex. Bound. 5
(1859).
Larger, 2.5 to 3.5 cm. in diameter, with longer tubercles (5 to 6
mm.), and more numerous (50 to 80) longer (3 to 5 mum.) spines
which are naked or nearly so. (Ill. Cact. Mex. Bound. t. 4)
Type, Wright specimen in Herb. Mo. Bot. Gard.
From western Texas (with the species) to Coahuila.
Specimens examined: Texas (Wright of 1852): Coahuila (Palmer of
1880).
In the Syn. Cact. Dr. Engelmann merges this variety with the
species, and has been followed in this by subsequent writers, but
the characters seem so (distinctive that its varietal rank has
been restored.