Cypripedium californicum

Plants erect, 25-120 cm. Leaves 5-10, along length of stem, alternate, ascending to spreading; blade elliptic-lanceolate to broadly elliptic, 5-16 × 1.5-6.5 cm. Flowers 3-18(-22); sepals yellow-green to pale brownish yellow; dorsal sepal elliptic, 14-20 × 7-13 mm; lateral sepals connate almost to apex; synsepal 12-20 × 10-12 mm; petals spreading, same color as sepals or more yellowish, linear-oblong to linear-lanceolate, flat, 14-16 × 3-5 mm; lip white, sometimes pinkish, obovoid, 15-20 mm; orifice basal, 11-14 mm; staminode suborbicular-subauriform.

Flowering May--Jun. Forest openings, especially on steep slopes, in seeps, springy marshes; 0--1600 m; Calif., Oreg.