Herbage puberulent or pubes­cent, glabrescent. Stems trail­ing or twining-climbing, to 900+ cm. Leaf blades broadly triangular, lobes 2(or 3)-pointed, basal sinus broadly rounded. Bracts broadly ovate, (19–)22–30(–37) × 17–30 mm, proxi­mally keeled or saccate, apex acuminate to rounded. Flowers: sepals 16–25 mm; corolla 47–68 mm; stamens 23–32 mm.

Flowering Feb–Aug. Bushy sites, grassy hillsides, rocky canyons, sand dunes; 0–500 m; Calif.

Subspecies amplissima intergrades with subsp. macrostegia.