This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Tormentilla reptans L. Sp. Pl. 500. 1753. Not P.
reptans L. Potentilla procumbens Sibth. Fl. Oxon. 162. 1794. Potentilla nemoralis Nestl. Mon. Pot. 65. 1816.
Diffusely branched, trailing or ascending, very slender, somewhat strigose-pubescent, 6'-2° long. Stipules foliaceous, entire or dentate; leaves petioled, 3-foliolate (rarely 5-foliolate); leaflets oblanceolate or obovate, obtuse at the apex, cune-ate at the base, sharply dentate above; peduncles axillary, filiform, usually much exceeding the leaves, 1-flowered; bractlets narrowly lanceolate; flowers 3"-4" broad, yellow, generally 4-parted; petals obovate, emarginate, or rounded, exceeding the acute calyx-lobes and narrowly lanceolate bractlets; achenes glabrous; receptacle pubescent.
Labrador and Nova Scotia. Naturalized from Europe. Called also trailing tormentil. Summer.
Potentilla rÚptans L., another European species found occasionally in grassy and waste places from Massachusetts to New Jersey, and recorded from Ohio, has 5-parted flowers with ovate or elliptic bractlets longer than the calyx-lobes.
Potentilla simplex Michx. Fl. Bor. Am. I : 303. 1803.
Potentilla canadensis simplex T. & G. Fl. N. Am. I: 443. 1840.
Rootstock short; stems slender, decumbent, ap-pressed-pubescent, 30 long or less. Leaves glabrous or nearly so above, silky appressed-pubescent beneath, the basal and lower ones 5-foliolate; stipules lanceolate; petioles appressed-pubescent; leaflets oblong to oblanceolate or obovate, coarsely toothed except near the base, 3/4' - 2 1/2' long; peduncles solitary in the axils of upper leaves, 1' - 2' long, appressed-pubescent; bractlets linear-lanceolate, 2" -2 1/2" long, about equalling the slightly broader calyx-lobes; petals yellow, obcordate, 2 1/2" - 3" long; stamens 20-25; styles filiform.
P. pumila Poir. in Lam. Enc. Meth. 5: 594. 1804. Potentilla canadensis pumila T. & G. Fl. N. A. 1: 443. 1840.
Low, seldom more than a few inches high; flowering stems at first very short and upright; later producing slender prostrate runners; whole plant densely silky-strigose, with appressed pubescence; basal leaves digitately 5-foliolate, on slender petioles; stem-leaves few and often only 3-foliolate; leaflets obovate, sharply serrate, usually less than 1' long; stipules small, lanceolate; flowers few, yellow, 3"-5" broad, the first from the axil of the first stem-leaf; petals broadly obovate, slightly exceeding the narrowly lanceolate sepals and bractlets; stamens about 20. In poor soil, Maine to Ontario, Georgia and Ohio. April-June.