Cal deeply cleft; cor open-campanulate, cleft to the middle or below; stamens distinct; 5 small, scale-like staminodia incurved over the ovary; anthers inflexed, with 2 pollen-sacs; style filiform; stigma obscurely 3-lobed; capsule ovoid; evergreen, rhizomatous, perennial herbs with long-petioled basal lvs and erect scapes bearing (in our sp.) a rather large, solitary fl. 8, the others e. Asian.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.