[3] Mammillaria vetula is a succulent subshrub[4] which forms clusters of globose to short-cylindric, bluish-green stems with axils that may be naked or slightly woolly.

[2] The flowers are funnel-shaped,[3] lemon-yellow, approximately 15 mm in length and width, with white (sometimes orange-yellow) stigmas.

It has 11 to 16 radial spines, 3 to 8 mm long, bristle-like, and chalky white (sometimes tipped brown in smaller variants).

Central spines are absent or number up to 5 in mature plants, measuring 10 to 12 mm long and stronger than radials, either white or dark brown.

[2] A form with smaller stems and brown spines also exists and is sometimes labeled M. fragilis or M. gracilis var.

Specific locations include San José del Oro, La Encarnación, Sierra de Jalapa, and Vizarrón.

The cacti nurseryman John Pilbeam speculates that, because of its plain spination and inconspicuous flowers, it was replaced by showier species.

[2] Pilbeam estimates that, because it breaks up into propagable pieces at the slightest touch and poses no problems in cultivation, M. vetula subsp.

[2] Mammillaria vetula are tough plants, but require good drainage and do best in sandy soil left to dry out between waterings.

Plants require a winter rest in a cold location, without watering, to encourage springtime blooming.