In our species, perennial herbs with opposite, entire leaves and small, 5-parted, campanulate, pink flowers in corymbed cymes, and slender elongated terete seed pods.

Stems 1—3 feet high, branches broadly spreading, mostly smooth. Leaves ovate or oval, spine-tipped, smooth above, pale and usually more or less hairy beneath. 2—4 inches long. Flowers pink, open-campanulate, ⅜ of an inch broad, with 5 spreading lobes, numerous, in loose, terminal and axillary cymes; seed pods round, slender, curved, 4—6 inches long, narrowed at the apex, usually in pairs; plant with a milky juice.

Frequent on the line of the railway from Field westward through the valley of the Kicking Horse River.