Potentilla supina L.

Bushy Cinquefoil

© SRTurner

Family - Rosaceae

Habit - Annual or biennial, rarely short-lived perennial forb.

Stem - Spreading to ascending, to 50 cm, sometimes multiple from the base, branched, moderately to densely pubescent with relatively long, fine, spreading hairs, occasionally glabrous toward the base.

	Stem.
© SRTurner

Leaves - Alternate, compound, petiolate, stipulate. Petioles 1-6 cm long, hairy. Stipules 5-15 mm long, leaflike, broadly lanceolate to broadly ovate, bluntly pointed at the tip, the margins entire or occasionally toothed and often hairy, the surfaces hairy, especially along the veins. Leaf blades 3-15 cm long, odd-pinnately compound with usually 5 or 7 leaflets, these 1-3 cm long, oblanceolate to elliptic or obovate, rounded to bluntly pointed at the tips, the margins coarsely toothed or scalloped, the upper surface green, sparsely to moderately hairy, the undersurface lighter green, moderately hairy.

	Stem and leaves.
© SRTurner

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

	Stipules.
© SRTurner

Inflorescence - Terminal panicles or racemes, mostly with numerous flowers, particularly later in the season.

	Inflorescence.
© SRTurner

	Inflorescence.
© SRTurner

Flower - Bractlets 5, 2-5 mm long, narrowly elliptic, sparsely hairy, more densely so along the margins. Hypanthia 3-4 mm in diameter, saucer-shaped to shallowly cup-shaped. Sepals 5, 3-6 mm long, broadly ovate, sharply pointed at the tips. Petals 5, 2.5-4.0 mm long, obovate, yellow. Stamens 20. Ovaries with the styles attached near the tips.

	Bractlets (fruiting). Sepals are appressed to fruit cluster and not fully visible in this view.
© SRTurner

	Corolla.
© SRTurner

Fruit - 0.7-1.3 mm long, smooth or somewhat wrinkled, brown, with a corky, winglike appendage along the inner margin.

	Fruiting head.
© SRTurner

Flowering - May - September.

Habitat - Streambanks, lake margins, railroads, roadsides.

Origin - Native to the U.S.

Lookalikes - Other species of Potentilla.

Other info. - This is one of the less common Missouri cinquefoils, thus far found exclusively in counties bordering the Missouri and Mississippi Rivers. It is easily differentiated from the other Missouri species of Potentilla by its pinnately compound leaves bearing five or more leaflets. The plant tends to flower quite profusely later in the season.

Missouri plants belong to ssp. paradoxa, which has an interesting distribution. Its main range is within the U.S. Plains longitudes, extending into the northwestern U.S. and Canada. Even within this region it is somewhat scattered. Counties which contain the species can be seen to follow the Missouri River beginning nearly at the river's origin in Gallatin County, MT. The plant follows the river throughout North and South Dakota, along the Iowa-Nebraska border, through Missouri, and for some distance downstream of the Missouri River's debouchment into the Mississippi. The strong implication is that the plant is uniquely adapted to floodplain areas subject to periodic flooding. In Missouri the plant appears to be somewhat waiflike, springing up somewhat sporadically, probably from seed deposited by flooding events.

Photographs taken at Klondike County Park boat ramp, St. Charles, MO, 5-15-2014, and at Riverfront Park, Washington, Franklin County, MO, 6-1-2018 (SRTurner).