There is only one member of the genus Sanguinaria, and here it is. These cheery little flowers pop up at about the same time as the Coltsfoots; this patch was blooming in early April beside a back road in Fox Chapel. The flowers open before the leaves are fully unfurled, so each flower stem is elegantly wrapped in a shell-like green leaf. The English and Latin names both come from the fact that the root is full of red juice.
Gray describes the genus and the species:
SANGUINARIA [Dill.] L. BLOODROOT. Sepals 2. Petals 8-12, spatulate-oblong. Stamens about 24. Style short; stigma 2-grooved. Pod ellipsoid or fusiform, turgid, 1-celled, 2-valved. Seeds with a large crest. — Low perennial; its thick prostrate rootstocks (surcharged with red-orange acrid juice) sending up in earliest spring a palmate-lobed leaf and 1-flowered scape. Flower white, handsome, the bud erect, the petals not crumpled. (Name from the color of the juice.)
S. canadensis L. — Open rich woods; common. Apr., May.