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..
Geum rivale L. Sp. Pl. 501. 1753.
Erect, simple or nearly so, pubescent, 1°-3° high. Basal leaves lyrately and interruptedly pinnate, petioled, the lateral segments generally few and small, the terminal 1-3, much larger, all sharply and irregularly lobed and dentate; stem-leaves distant, short-petioled or sessile, simple, or 3-foliolate; flowers few, terminal, purple or purplish, nodding, 9"-12" broad; petals obovate, emarginate, abruptly narrowed into a claw; calyx-lobes spreading, purple; head of fruit stalked in the calyx; achenes pubescent; style jointed, plumose below, 3"-4" long.
In swamps and low grounds, Newfoundland to British Columbia, New Jersey, Pennsylvania, Michigan and Colorado. Also in northern Europe and Asia. Indian-chocolate. Evan's- or chocolate-root. Drooping avens. Maiden-hair. Throatwort. Throat-root. Cure-all. May-July.