Cereus forbesii, from Bolivia and Argentina, recently has been lumped into Cereus validus, but the description does not remotely match these plants. For one thing, the typical species is a columnar cactus with 4-sided stems, and for another, these plants are a monstrose version of that typical plant. The flowers are the typical Cereus form, large and white with purple hues. These plants are rooted offsets in 4-inch pots.