Sp. Pl. 1: 505. 175
Gen. Pl. ed. 5, 223. 1754
Herbs, perennial, scapose, from thick rhizomes; sap orange to red. Leaves 1, or few and rosulate, sheathing-petiolate; blade 1× palmately lobed. Inflorescences terminal, 1(-3)-flowered; bracts absent. Flowers: sepals 2, distinct; petals 6-12, unequal; stamens many; pistil 2-carpellate; ovary 1-locular; style ± distinct; stigma 2-lobed. Capsules erect, 2-valved, dehiscing from base. Seeds few to many, arillate. x = 9.
Sanguinaria is similar, and probably most closely related, to Eomecon Hance of eastern Asia, which is monotypic also.