Synonyms: Other names: nodding avens, water avens Nomenclature: rivale = growing by streams Nativity / Invasiveness: Montana native plant
General: perennial with short to rather extensive, scaly rootstocks. Flowering stems mostly 40-60 cm tall, mostly stiff-hairy but becoming softly short-hairy above.
Leaves: the basal ones several, up to 30 cm long, pinnately divided, the leaflets mostly 7-15, once or twice round- to sharp-toothed, the 3 at the end much larger, obovate to wedge-shaped, up to 10 cm long. Stem leaves 2-5, alternate, reduced, the stipules leafletlike, the blades pinnatifid below to deeply 3-lobed above.
Flowers: bell- to urn-shaped, about 3 to 7 in an open cluster, the flowers nodding in the bud but becoming erect. Calyx reddish-purple, the 5 lobes lanceolate, pointed, about 10 mm long, erect. Petals 5, rounded, yellow to pinkish, not spreading, mostly 2-3 mm shorter than the sepals. Stamens 100 or more. Styles bent at joint near tip.
Fruits: achenes, elliptic, 3-4 mm long, stiff-hairy, the lower (persistent) joint of the style 6-8 mm long, stiff-hairy below, hairless above, hooked at the tip, the upper segment ultimately dropped, sparsely stiff-hairy, 3-4 mm. long.
Stream banks, lake shores, bogs, and wet meadows, in w. and c. parts of MT. Also from B.C. and Alberta to WA, s. in the Rocky Mts. to NM, e. to MO, IN, NJ, and in Eurasia.
The dried or fresh root can be boiled in water to make a delicious chocolate-like drink. It can also be used as a seasoning. It is best harvested in the spring or autumn but can be used all year round. Fragrant, it was once used to flavor ales.
The root is anti-inflammatory, antiseptic, aromatic, astringent, diaphoretic, febrifuge, stomachic, tonic, and has agents that check bleeding by contracting blood vessels. An infusion is taken internally in the treatment of diarrhea (and is suitable for children to use), intestinal and stomach complaints, liver disorders etc, it is also applied externally as a wash to various skin afflictions - it is said to remove spots, freckles and eruptions from the face. This plant has similar properties but is less active than the related G. urbanum and so is seldom used medicinally. The root is best harvested in the spring, since at this time it is most fragrant. Much of the fragrance can be lost on drying, so the root should be dried with great care then stored in a cool dry place in an airtight container, being sliced and powdered only when required for use. The root is rich in tannin and is a powerful astringent.