Gymnocalycium schroederianum has a dark grey-green, depressed-spherical stem, reaching up to 7 cm tall and 14 cm wide, with about 24 broad, rounded ribs divided by prominent tubercles. It features around 7 radial spines, initially pale yellow and later ash-grey with red bases, varying in length, with the longest spine typically reaching the
areole below. Flowers bloom near the apex, are bell- or funnel-shaped, about 70 mm long and 55 mm wide, with a slender tube adorned with olive-green, white-edged kidney-shaped scales, and pale greenish-white or yellowish-green perianth segments. The plant blooms readily from June through autumn, even as a young seedling, and produces narrowly pear-shaped, pale grey-green fruits around 25 mm long, containing matte black seeds. ==Distribution==