Cactus pusillus DC. Cat. Hort. Monsp. 184 (1813), not Haw.
(1803).
Mamillaria pusilla DC. Prod. iii. 459 (1828).
A very common West Indian species, apparently differing from the
variety only in the very much fewer (12 to 20) radial spines,
although numerous specimens, both dried and living, were examined
for additional characters. This difference, however, is so
constant and striking that, taken together with the wide
geographical separation, it should stand as varietal.