Cal cleft to near the base, exappendiculate, accrescent and subrotate at maturity; cor campanulate, white to lavender, about equaling or slightly surpassed by the cor, cleft to half its length; ovules 2 on each of the 2 expanded parietal placentas; fr unilocular, 2-valved; seeds finely reticulate, without a cucullus; small, branching annuals with pinnatifid lvs, at least the lower ones opposite, the fls solitary in or opposite the axils, the stem sometimes also terminating in a lax, few-fld infl. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.