25. Sanguisorba Linnaeus, Sp. Pl. 1: 116. 1753; Gen. Pl. ed. 5, 53. 1754.
Burnet, sanguisorbe [Latin sanguis, blood, and sorbeo, to absorb, apparently alluding to traditional European and Asian uses to stop external or internal bleeding, suggested by dark red flowers of some species and medieval doctrine of signat
Alan S. Weakley
Herbs, perennial, 2–20 dm; rhizomatous. Stems 1–10+, ascending to erect, glabrous or glabrescent. Leaves deciduous, basal and cauline; stipules persistent, adnate to petiole, free portion usually ovate, obovate, or suborbiculate, margins dentate; petiole present; blade oblong-elliptic, 5–55 cm (basal blades largest, cauline reduced distally), herbaceous, leaflets (3–)7–21, orbiculate, ovate, or oblong, ˂leafy stipels sometimes present on vigorous leaves˃, margins flat, crenate or serrate, surfaces glabrous or sparsely hairy. Inflorescences terminal or axillary to distal leaves, 50–500+-flowered, spikes, ˂ellipsoid to cylindric˃, glabrous or variously pubescent; peduncles present; bracts absent; bracteoles present. Pedicels absent. Flowers 2–5 mm diam.; hypanthium urceolate, 1–6 mm, ˂smooth, muricate, or winged˃, glabrous; sepals 4, ˂basally connate˃, spreading, petaloid, elliptic to ovate; petals 0; stamens [2–]4[–12], shorter or longer than sepals; carpels 1[or 2], glabrous, ˂styles repeatedly branched, brushlike; ovules pendulous˃. Fruits achenes, 1, globose, 0.5–2 mm, glabrous; hypanthium persistent, enclosing achenes, ˂dry, hardened, top-shaped to ellipsoid, 2–5 mm, 4-angled or -winged, faces smooth between angles˃; sepals persistent, spreading to ascending. x = 14.
Species ca. 15 (4 in the flora): North America, n Eurasia.
Sanguisorba is here circumscribed more narrowly than it has been traditionally (for example, H. A. Gleason and A. Cronquist 1991) (though exactly as it was circumscribed by P. A. Rydberg 1908–1918), based on recent molecular phylogenetic analyses summarized in D. Potter et al. (2007), following and refining initial findings by M. S. Kerr (2004). Poteridium and Poterium are in a clade separate from Sanguisorba and basal in Sanguisorbeae, with Sanguisorba then basal to the remainder of Sanguisorbeae (Potter et al.).
Acropetal flowering refers to flowers opening sequentially from the base toward the apex of the inflorescence. Basipetal flowering refers to flowers opening sequentially from the apex toward the base of the inflorescence.