The silver ball cactus gets its name from its silvery white areoles and its nearly perfectly spherical stem. This cactus boasts one of the loveliest flowers of all the cacti species, with its long, narrow, delicate, canary-yellow petals and red pistil. The blossoms sprout in a ring near the top center of ball, forming a feathery golden halo. The silver ball originates in Brazil and Uruguay.