[2] Gymnocalycium ragonesei is a cactus usually grows solitary, with greenish-gray to dull brown, very flattened spherical stems that barely rise above the ground, reaching up to 5 cm in diameter.

Up to six thin, almost hair-like white spines, darker at the tips, grow up to 3 mm long.

The white flowers have a faint reddish throat, measuring 3–4 cm in both length and diameter.

The greenish-brown, egg- to spindle-shaped fruits grow up to 2.5 cm long.

[4] Described in 1950 by Alberto Castellanos, its species name honors Argentine botanist Arturo Enrique Ragonese.