Swamp larkspur

Stems 10-30(-70) cm; base reddish or not, nearly glabrous. Leaves mostly on proximal 1/4 of stem; basal leaves 6-8 at anthesis; cauline leaves 0-5 at anthesis; petiole 0.3-7 cm. Leaf blade obdeltoid, apically several parted, 1-8 × 1-7 cm, ± fleshy, glabrous; ultimate lobes 0-3, width 3-20 mm (cauline only); margins of basal leaf, measured less than 1 cm from blade base, demarcating less than 90° of arc when leaf laid flat. Inflorescences 5-20(-48)-flowered, ± open; pedicel 0.3-3(-10) cm, glabrous to puberulent; bracteoles 2-3(-5) mm from flowers, green to blue, lanceolate-linear, 3-4(-7) mm, puberulent. Flowers: sepals dark blue, nearly glabrous, lateral sepals spreading, 9-15 × 5-8 mm, spurs usually upcurved, ascending 30-45° above horizontal, 10-14 mm; lower petal blades slightly elevated, ± exposing stamens, 4-5 mm, clefts 2-3 mm; hairs centered, densest on inner lobe above base of cleft, also on margins, white. Fruits 10-18 mm, 4.1-4.5 times longer than wide, puberulent. Seeds: seed coat cells with surfaces bumpy or wavy. 2 n = 16.

Flowering late spring-early summer. Serpentine streamsides, chaparral, grassland; 400-600 m; Calif.

Although some populations are large, Delphinium uliginosum is very local. Hybrids with D . hesperium subsp. pallescens have been seen.

Delphinium uliginosum is a very distinctive species, not likely to be confused with any other. The fan-shaped, slightly dissected leaves are apparently unique in the genus.