Astrophytum asterias is a species of cactus in the genus Astrophytum, and is native to small parts of Texas in the United States and Mexico. Common names include sand dollar cactus, sea urchin cactus, star cactus and star peyote.
A. asterias (also known as the Star Cactus) is small, round, spineless and squat, reaching a height of 2.5–6 cm (0.98–2.36 in) and a diameter of 5–15 cm (2.0–5.9 in). The disc-shaped body is divided into 7 – 10 sections, known as ribs; in the middle of each rib there are woolly areoles. The body is a greenish-brown color and may appear speckled from its covering of white scales (trichomes). The flowers of this cactus are yellow with red bases and the outer parts are very woolly. Green to pink oval fruits are produced; the outside coat is covered with woolly hairs.
Sand Dollar Cactus has been grown as a houseplant since the 1840s, like other members of its genus and despite its rarity in the wild. It is readily propagated from seed, so most plants encountered in nurseries are seed grown. The popularity of this species among collectors and enthusiasts has ensured that a number of cultivars are available. One such cultivar is the ‘Super Kabuto’, a clonally propagated variety whose large trichomes congregate into dense spots, arranged in a striking pattern.
Reference: Wikispecies: Astrophytum asterias