Synonyms include Echinocactus myriostigma, Astrophytum prismaticum, A. columnare, A. tulense, and A. nuda.

Astrophytum myriostigma is a spineless cactus defined by the presence of three to seven (usually five) pronounced vertical ribs which define the cactus' shape when young (the genus name "astrophytum", literally, "star plant", is derived from the resulting star-like shape).

In the wild, globose to cylindrical stem is covered with a whitish flocking of trichomes.

In the wild, the cacti flower in early spring, so that their seeds can grow with summer rains.

Plants produce one or more flowers 4–6 cm (1.6–2.4 in) diameter near the apex; the numerous tepals are creamy yellow, sometimes with an orange or red base.