Sep and pet persistent, the sep nearly as long as the pet but more greenish; stamens 9, the outer cycle of 3 pairs of obliquely antesepalous members, the inner of 3 directly antepetalous members, so that all spread at equal angles from the receptacle.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.