Flowering stems 5-60 cm. Leaf blades 1-11 cm wide, 5-13-lobed for 1/4-1/2 length, lobes cuneate-oblong to subovate, 1-2 times dentate to subcrenate. Flowers: sepals triangular-ovate, 0.6-1.3 × 0.6-1 mm; petals ovate and abruptly clawed to ovate-lanceolate and more gradually narrowed into claw; ovary ± as long as wide. Capsules cylindric-ovate, 3.2-8 × 1.5-4 mm, to 2.5 times longer than wide. Seeds 0.9-1.6 mm. 2n = 14.

Flowering Jun-Aug. Moist cliffs, stream banks, springs, near waterfalls, typically on limestone; 900-2500 m; Idaho, Mont., Wyo.

Variety hapemanii occurs in the Bighorn Mountains of north-central Wyoming and Bighorn Canyon of south-central Montana, with outliers in the Owl Creek Mountains and northern Laramie Range, Wyoming. It is also disjunct in the middle fork of the Salmon River in central Idaho.