Aquatic and Wetland Vascular Plants of the Northern Great Plains
26. Rosaceae, the Rose Family
2. Potentilla L. -- Cinquefoil
1. Potentilla anserina L. -- Silverweed
Low, extensively stoloniferous perennial from a stout rootstock; leaves
basal except for a few clustered on the stolons, pinnately compound with numerous
leaflets, small leaflets often alternating with larger ones; blade oblanceolate
in outline; 0.5-3(5) dm long, including the petiole which may be 1/2 the total
leaf length, 2-8 cm wide, green and glabrous to grayish-green and sericeous
above, densely white-tomentose beneath; leaflets elliptic to oblong or
obovate, 1.5-5 cm long, 0.5-1.8 cm wide, greatly reduced downward, deeply serrate,
the teeth sharply ascending; stipules prominent as brownish membranous
wings on the basal portion of the petiole. Flowers yellow, rather showy,
solitary from the leafy nodes of the stolons, on peduncles 4-15(25) cm long;
sepals ovate, acuminate, white-sericeous on the outside; petals
elliptic to obovate or nearly rotund, 5-10 mm long; stamens 20-25; pistils
numerous, styles attached laterally on the ovary. Mature achenes golden
brown, obliquely ovoid, usually corky with ridges or furrows. Jun--Aug. Wet
meadows, ditches, shores, stream banks and mud flats; common and often weedy
in ND, e MT and e SD, otherwise scattered in w SD, e WY and w NE; (Circumboreal,
in N.Amer. s to NY, IN, IA, NE, NM and CA).