Potentilla norvegica L.
CC = 0
CW = 3
MOC = 67
Family - Rosaceae
Habit - Taprooted, annual, biennial, or rarely short-lived perennial, forbs.
Stems - Ascending to erect, to 60 cm, multiple from base, branching, moderately to densely pubescent with straight to somewhat woolly hairs, the hairs often with minute, pustular bases, rarely glabrous or nearly so.
Leaves - Alternate, trifoliate, petiolate, stipulate, much reduced upward. Petioles 1-6 cm long, sometimes nearly absent toward the stem tips, hairy, with adaxial groove. Stipules 5-20 mm long, ovate, sharply pointed at the tip, the margins entire or toothed, hairy. Leaf blades 2-6 cm long, palmately or pinnately trifoliate, a few of the leaves rarely with 5 leaflets, these 1-6 cm long (the central leaflet the largest, sessile or short-stalked), broadly oblanceolate or elliptic to obovate or broadly obovate, rounded to bluntly pointed at the tips, the margins coarsely toothed, the upper surface green, glabrous or sparsely to moderately hairy, especially along the veins, the undersurface lighter green, moderately hairy, especially along the veins.
Inflorescence - Terminal, relatively small, flat-topped to shallowly domes-haped clusters of several flowers. Pedicels to 9 mm, elongating in fruit, pilose to hirsute.
Flowers - Bractlets 4-8 mm long, oblanceolate to narrowly elliptic, moderately hairy. Hypanthia 4-5 mm in diameter, shallowly cup-shaped to nearly disc-shaped. Sepals 3.5-6.0 mm long, broadly ovate, sharply pointed at the tips. Petals 3-5 mm long, obovate, shallowly and broadly notched at the tip, yellow. Stamens about 20. Filaments yellowish, to 2 mm long, glabrous. Anthers yellow. Carpels many, yellowish. Ovaries with the styles attached near the tips.
Fruits - Achenes 0.8-1.2 mm long, the surface usually coarsely wrinkled or longitudinally ribbed, brown to greenish brown, unwinged.
Flowering - May - October.
Habitat - Streambanks, pond margins, bases of bluffs, prairies, sand prairies, bottomland forests, pastures, fields, barnyards, railroads, roadsides, open disturbed areas.
Origin - Native to the U.S.
Lookalikes - P. simplex, other species of Potentilla.
Other info. - This plant is found scattered across most of Missouri, and throughout the continental U.S. except for the states of LA, AL, and FL. The plant has the characteristic appearance of a Potentilla, with compound leaves and toothed leaflets, and bright yellow flowers with five distinct petals and numerous stamens. This species is distinguished from other Missouri members of the genus by having three leaflets on most leaves. It is less common than P. simplex but still encountered fairly frequently. Some authors have defined varieties on the basis of pubescence characters.
Photographs taken at the Kansas City Zoo, 7-3-00, in Pictured Rocks National Seashore, MI., 7-21-02, and in the Ozark Scenic Riverways, Shannon County, MO., 5-18-03 (DETenaglia); also at Klondike County Park, St. Charles County, MO, 6-23-2014, and along the Katy Trail near Dutzow, Warren County, MO, 5-14-2020 (SRTurner).