Astrophytum myriostigma is a spineless cactus, usually solitary or with very few basal branches. Globular to cylindrical stem up to 3.3 feet (1 m) and up to 8 inches (20 cm) in diameter, bright green, covered with many minute white hairy scales. Usually 5 ribs, sometimes 3 or 4, increase to 8 or more with age (rarely even 10). Funnelform flowers, up to 3 inches (7.5 cm) long, glossy yellow and sweet scented from the areole at the tip of the stem on mature plant. Greenish to tannish-red fruits, up to 1 inch (2.5 cm) in diameter, covered with brown, overlapping scales, with long wool in their axil.