The genus contains some interesting plants, with globular or small columnar ovoid, forming plump . The spines are numerous and strong. The are borne on the young areoles, and are usually yellow in colour.
Echinocactus Grusonii. Central Mexico. A very popular plant with growers, found in most collections. The light green stems are solitary, globose or cylindrical according to age, and the ribs may vary in number from 20 to 30. When young the spines are pale golden-yellow, turning almost white as plants get older. Radial spines number 8 to io, central spines 3 to 5. Theare yellow and open during sunshine, but are never fully open.
Echinocactus ingens. Mexico. Theis globular or elongated, sea-green with purplish brown shading, and very woolly at the top. This is one of the largest of the spherical cacti. In young plants, the ribs number 5 to 8, but old plants possess many ribs. The areoles are large, with abundant yellowish wool, each bearing 8 radial spines and 1 central spine. The flowers are reddish-yellow outside and yellow inside.
Echinocactus ingens visnaga. Young plants are globular, but they become elongated with age. The plants are greyish-green with tawny wool at the top. There are up to 40 ribs with roundish or elongated areoles bearing pale brown-ringed spines, 4 thick and 6 thin, spreading crosswise; the upper part of the spine is thick and long. Flowers, yellow.
Echinocactus horizonthalonius. Texas, New Mexico to Arizona and N. Mexico. This is a small and beautiful species. The pale sea-green stem is solitary, globular or cylindrical, with 7 to 13 ribs, rounded and frequently spirally arranged. The areoles are woolly and contain 6 to 9 spines; the single central spine, when present, is even stronger than the marginal ones. The flower is beautiful, pale pink in colour, and striking against the sea-green stem.