Barrel Cactus, Echinocactus, for my second Cactus Monday sponsored by Teri C.
They have that name for a good reason, they are shaped like a barrel with long yellow spines. They are sometimes referred to as the compass plant because to prevent sunburn they grow south. This types of cactus also produce small suckers from the base of the plant. It produces flowers late in the year after most types of cactus have already flowered.