Sep usually 4, uniseriate, early deciduous; pet usually 8, biseriate; ovary ovoid, with many ovules and a broad, sessile stigma; fr capsular, obovoid or pyriform, opening in the distal half by a horizontal cleft extending half way around it, the top forming a lid; smooth perennial herbs with a few basal lvs deeply divided into 2 obliquely half-ovate segments, the fls solitary on a naked scape. 2, the other in Manchuria.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.