Fr elliptic to broadly ovate-oblong, slightly compressed laterally or somewhat compressed dorsally, in the latter case with marginal wings; dorsal ribs low, oil-tubes mostly 3 in the intervals and 4 on the commissure; carpophore bifid to the base; umbels terminal, often some of them elongate, lf-opposed pedicels; invol and involucel generally wanting; umbels loose and open, with mostly 7-16 spreading or ascending rays, the outer rays the longer (especially in fr) and bearing umbellets with marginal fertile fls and inner staminate ones, the inner rays bearing staminate umbellets; sep minute or obsolete; pet yellow; stylopodium wanting; glabrous, somewhat glaucous perennials from tuberous-thickened roots, with basal and cauline, mostly 2 or 3 times ternate lvs and entire, mostly discrete lfls; 2n=22. 2, e. U.S.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
