Etymology - From the Greek thele which means "nipple" - making reference to the tubercles.Thelocactus is comprised of a dozen species that are found primarily in the Chihuahuan desert of Texas and Mexico. The species have feature small globose or short cylindrical stems that are solitary or form small clusters. The stems have ribs that are strongly or entirely tuberculate and are often topped with stout, needle-like spines, which are hooked in some species. Flowers are white, pink, or yellow and often are a combination of colors, either in concentric rings or strips. The flowers are usually large in proportion to the stems and come from the top of the plant. Flowers may also continue during the entire summer.
The manageable size of the plants and the readiness to flower in conjunction with the ease of care make many species in this genus very popular in cultivation.