Echinocactus grusonii is a well known species of cactus native to central Mexico from San Luis Potosi to Hidalgo. It is commonly known as the Golden Barrel Cactus, Golden Ball or, amusingly, Mother-in-Law's Cushion. It belongs to the small genus Echinocactus, which together with the related genus Ferocactus, are commonly referred to as barrel cacti. Growing as a large roughly spherical globe, it may eventually reach over a metre in height after many years. There may be up to 35 pronounced ribs in mature plants, though they are not evident in young plants, which may have a knobbly appearance. Note: Younger Golden Barrels do not look similar to the mature ones. The sharp spines are long, straight or slightly curved, and various shades of yellow or, occasionally, white. Small yellow flowers appear in summer around the crown of the plant, but only after twenty years or so. Widely cultivated in warmer climates around the world, it is considered easy to grow and relatively fast growing.