Hydrophyllum tenuipes, commonly known as Pacific Waterleaf, is a member of the Hydrophyllaceae plant family. Plants are herbaceous, perennial and often covered in hairs appearing soft and fuzzy to the naked eye. Solitary stems standing up to 80 cm tall but typically between 30-40 cm, are borne from a shallow rhizome with fleshy fibrous roots in the spring. Large leaves (15cm x 15cm) divided into 5, 7 or 9 segments (usually 5) with toothed margins are alternately arranged along the stem on 5-12 mm long pedicels. Small (5-7 mm long) flowers have greenish-white to lavender petals, are bell shaped and arranged in compact subdichotomously branched cymes with no developed main stem produced from the upper leaf axils on a peduncle 10.15 cm tall. The fruit is a single-chambered capsule opening by two valves and producing 1-3 seeds.
The habitat of Pacific Waterleaf is in moist woods at lower elevations west of the Cascades and the Pacific Northwest. A true shade lover, H. tenuipes is most prolific on moist, rich bottomlands. Populations of H. tenuipes show environmental plasticity evidenced by nearly blue flowers produced on plants of the same species showing up on the Olympic Peninsula and in Port Angeles.
Historically the roots of H. tenuipes were eaten by the Cowlitz of western Washington. The roots of an interior relative (H. capitatum or Ballhead Waterleaf) was eaten by the plateau people. The rhizome of H. tenuipes exudes a peppery smell when cells are broken.