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..
Erect, perennial herbs, sometimes decumbent at the base, with alternate odd-pinnate stipulate leaves and small perfect or polygamo-dioecious flowers in dense terminal peduncled spikes. Calyx-tube turbinate, constricted at the throat, angled or winged, persistent, 4-lobed, the lobes petaloid, concave, deciduous. Petals none. Stamens 4, inserted on the throat of the calyx; filaments filiform, elongated, exserted; anthers short; carpel enclosed in the calyx-tube opposite the sepals. Style filiform, terminal; stigmas papillose; ovule suspended. Achene enclosed in the dry angled calyx. Seed pendulous. [Latin, blood-staunching, from its supposed properties.]
About 10 species, natives of the north temperate zone. In addition to the following, 2 or 3 others occur in the western parts of North America. Type species: Sanguisorba officinalis L.
Sanguisorba canadensis L. Sp. Pl. 117. 1753. Poterium canadense A. Gray, Man. Ed. 5, 150. 1867.
Glabrous or slightly pubescent toward the base, erect, simple, or branched above, 1°-6° high, the branches erect. Stipules often foliaceous and dentate; basal leaves long-petioled, sometimes 2° long; leaflets 7 - 15, ovate, oblong, or oval, obtuse or acutish, cordate or obtuse at the base, serrate with acute teeth, stalked, 1' - 3' long; flowers white, perfect, bracteolate at the base, in dense terminal showy spikes 1' - 6' long; stamens 4; filaments long-exserted, white; achene enclosed in the 4-winged calyx.