Lupinus arizonicus (S. Watson) S. Watson
Arizona lupines are natives of the Mojave and Sonoran deserts in the American southwest and northwestern Mexico. They prefer washes, sandy flats, and hillsides, at elevations below 3500' (1 km).
Plants: 4-20" (10-50 cm) high, topped by a hairy spike of flowers.
Leaves: Leaves are palmate, comprised of 6-10 narrow leaflets, like spokes on a wheel, on petioles (stems) up to 3" (7.6 cm) long. The spokes of the wheel are thought to gather rainwater, concentrating it at the center of the wheel in order to absorb every precious bit. Leaflets are ⅜-1½" (1-4 cm) long and 1¾-4" (5-10 cm) wide, so each palmate leaf cluster is up to about 3" (8 cm) in diameter. Leaves may be curled along the edges, resembling pea pod halves in shape. Upper leaf surfaces are hairless, while lower surfaces have sparse hairs.
Flowers: Flowers are large spikes filled with striking dark pink to magenta flowers that age to purplish blue. They spiral around the stem. Each flower is ¼-⅜" (7-10 mm) long, and is supported by a small, hairy bract. The upper petal has a yellow spot, changing to red after the flower is pollinated. Flowers appear from March to May.
Fruits: pods ⅜-¾" (1-2 cm) × ⅛" (5 mm), often on one side of the flowerhead, covered with coarse hairs. Upon ripening, seed pods dry and explode to scatter seed.
Lupinus arizonicus on www.americansouthwest.net
Lupinus arizonicus on DesertUSA: Exploring the Southwest
Lupinus arizonicus at Southeastern Arizona Wildflowers and the Plants of the Sonoran Desert
Lupinus arizonicus at the Sonoran Desert Naturalist
Lupinus arizonicus from the Jepson Manual
Lupinus arizonicus description by Thomas H. Kent, last updated 25 May 2020.