Infl ±congested or of open cymes; cal cylindric, membranous, 20-nerved; pet with distinct claw and blade, the appendages conspicuous, subulate; stamens 10; styles 2(3); capsule dehiscent by 4(-6) teeth; seeds rotund-reniform, uniformly reticulate; perennial herbs. 30, temp. Eurasia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.