From northern Argentina, Echinopsis aurea is a sometimes clumping cylindrical cactus to 6 inches tall and 4 inches across. It produces yellow, red, pink or white flowers that come in flushes in spring and summer. I think it's common name came about because it was first described with yellow flowers.
     This came from Miles Anderson as Lobivia ancastii. I love the flowers. After it's flowering is done I'll get a pic of the body of the plant.