Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
26. Rosaceae, the Rose Family
2. Potentilla L. -- Cinquefoil
5. Potentilla rivalis Nutt. -- Brook cinquefoil
Erect to spreading, hirsute, taprooted annual or biennial 1.5-9 dm tall, simple
or branched from the base, branched above. Leaves mostly cauline, long-petioled
below to subsessile above, palmately compound, with 3-7 leaflets, or the lower
leaves closely pinnate, the leaflets obovate to elliptic or oblanceolate, 1.5-5
cm long, 0.5-2.5 cm wide, coarsely serrate; stipules ovate, usually toothed,
mostly 0.5-1.5 cm long. Flowers numerous in leafy, branched cymes, not
showy; sepals ovate-triangular, 2.5-6 mm long, the bractlets sometimes
longer; petals yellow, obovate to oblanceolate, 1-1.5(2) mm long, ca.
1/2 or less as long as the sepals; stamens 10-15; styles terminal.
Achenes yellowish, ovoid-reniform, 0.6-0.8 mm long, smooth. Jun--Aug.
Wet meadows, shores, ditches, stream banks and flats; frequent; (IL and MN to
B.C., s to MO, TX, Mex. and CA). P. millegrana Engelm.
Potentilla biennis Greene is a similar species of moist woodlands
and stream banks that has been reported for w SD. It differs from P. rivalis
as follows: Averaging smaller, (1)3-6 dm tall, the stems and leaves
with fine glandular hairs as well as longer eglandular hairs; leaves
all 3-foliate; calyx mealy-glandular.
Previous Species -- Potentilla paradoxa Nutt.
ex Torr. & Gray -- Bushy cinquefoil
Return to Family -- Rosaceae - The
Next Species -- Spiraea alba Du Roi