This, I am pretty sure, is a young Old Man Cactus, growing on a ridge overlooking Bahia Magdalena in Baja, Mexoco. When the cactus gets larger gray, hair-like spines grow out of the top, giving it a whiskered look, akin to an old man. The Cactus has small, pale pink flowers in the spring, which open at night, pollinated by bats and insects. Indians used to make tea from the cooked, sliced stalks to help relieve ulcerated stomachs. On the Mexican mainland slices of this species are sold in markets, used as a treatment for stingray wounds. The chopped stems were used to stupefy fish, also used as cattle forage.
The small red fruit was eaten by aborigines when other food was scarce.