Arroyo lupine

Lupinus succulentus Douglas ex K.Koch (Fabaceae), the arroyo lupine or hollowleaf annual lupine, is a stout, fleshy-stemmed annual herb 30-100 cm tall, native to California and northern Baja California, where it is common in disturbed clay soils, roadsides, grasslands and open coastal scrub. The robust, hollow, glabrous to sparsely hairy stems support palmately compound leaves with 7-9 obovate, succulent leaflets 2-6 cm long, each glabrous above and short-pubescent beneath. Inflorescences are dense erect terminal racemes 10-30 cm long bearing showy pea flowers with a deep violet to royal-blue banner marked by a central white to yellowish patch that ages magenta after pollination, signaling pollinators (chiefly bumblebees) to ignore older flowers. The fruits are flattened, densely silky-pubescent pods 3-5 cm long that twist explosively on dehiscence, ejecting 5-8 mottled brown seeds. Seeds contain quinolizidine alkaloids typical of the genus and are not safe to eat raw.