The other-worldy Cirio tree (Idria [Fouquieria] columnaris), also known as the Boojum tree, is endemic to the Baja California peninsula, and a small area of desert in the Mexican state of Sonora. Growing up to 55 feet in height, many agree that the strange plant looks like something out of a Dr. Seuss book. It grows in a tall columnar tapering trunk. Many Cirios' trunks grow into an array of strange curves and twists, and older organisms branch into several stems at the top, which present a spreading crown of creamy white flowers between July and August. The Cirio grows very slowly, taking up to 27 years to grow only 3 feet.

Although of little economic use, the Cirio is an important part of Baja California's landscape and biodiversity. The Cirio is one of the few plants in the region that has resisted Dodder and Mistletoe, two parasitic plants common on the peninsula. With the exception of the Cardón, the Cirio is the tallest plant in the Baja California and Sonoran deserts.