Cal-tube cupulate, the 4 lower lobes oblong, obtuse, about equaling the tube, the upper median lobe shorter and narrower; cor- tube narrowly campanulate, longer than the lobes, densely hairy within, the lobes all about alike and widely spreading; stamens 4, paired; filaments villous, inserted near the middle of the cor-tube, scarcely exsert; anthers glabrous, oblong, dehiscent throughout; style short; stigmas 2; fr round-ovoid, loculicidal, each valve with a short, flat, triangular beak; seeds angular, with papery, reticulate outer coat. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
