California barrel cactus
Ferocactus cylindraceus
Family: Cactaceae.
Type: Perennial plant.
Leaves: Leaves are modified into spines that curl around the barrel.
Twig: Grows as a single barrel, usually unbranched. The barrel is green and photosynthetic. It has ribs that allow the barrel to expand and contract with the amount of water it stores. The ribs may also contribute to self-shading.
Fruit & Flower: Flowers are big and showy.
Miscellaneous: No other comments.