Plants: erect, perennial, 1'-3' tall, branched, smooth forb from a thickened cluster of roots
Leaves: basal leaves undivided and with a heart-shaped base, coarsely toothed, long-stalked; upper leaves 1 or 2 times 3-parted
Flowers: yellow, 5-parted; inflorescence a compound umbel, each umbellet with many irregularly-stalked flowers, the central flower often not stalked; blooms May-June
Fruits: dry, splitting into 2 seeds, - fruit: seed:
Habitat: full sun; moderate moisture to wet; in sandy, loamy soil
Conservation Status: Native
Herbs: 2--6 dm. Leaves: basal usually simple, rarely ternate; petiole 4--7 cm; blade cordate to ovate,4--10(--15) x 3--7(--10) cm; leaflet margins finely crenate-dentate, teeth 4--10 per cm, apices acute to obtuse, apex usually rounded to obtuse, sometimes acute, cauline leaves usually ternate, sometimes simple and unlobed or 3-lobed, blade margins serrate. Umbels: rays 7--16, 1--3(--5) cm; involucel bractlets linear, 1--2 mm. Pedicels: lateral 1--3 mm. Mericarps: oblong to ovate, 2--4 x 2 mm. 2n = 22.
Flowering Apr--Jun. Mesic to dry forests and woodlands, openings, prairies, roadsides; 10--2600 m; Alta., B.C., Man., Ont., Sask., Yukon; Ala., Ark., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Ky., Md., Mich., Minn., Miss., Mo., Mont., Nev., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Utah, Va., Wash., W.Va., Wis., Wyo.
Zizia aptera is scattered throughout its wide distribution. It is listed as rare in Indiana, threatened in Michigan, endangered in Connecticut, and historical in Rhode Island. Reports from Quebec are based on old collections; it did not become naturalized there.
Thaspium trifoliatum and Zizia aptera sometimes are confused. Vegetatively they are extremely similar, and although it has been suggested that they can be distinguished by stem pubescence and leaf blade tooth characters (for example, A. S. Weakley 2015), these characters do not work through much of their ranges. They are best distinguished by the root, pedicel, and fruit characters that separate the genera.
The illegitimate name Zizia cordata W. D. Koch ex de Candolle, based on the illegitimate name Smyrmium cordatum Walter (itself a superfluous name for Thapsia trifoliata Linnaeus), has sometimes been treated as a synonym of Z. aptera.
Geoffrey A. Levin
Type Specimen: “New York & New Jersey”, without data, Gray s.n. (lectotype: GH). Lectotypified by Fernald, Rhodora 41: 444. 1939. Global Plants