Artemisia biennis

Annuals or biennials, (10-)30-80(-150) cm, not aromatic. Stems 1, erect, often reddish, simple (finely striate), glabrous. Leaves cauline, green or yellow-green (sessile); blades broadly lanceolate to ovate, 4-10(-13) × 1.5-4 cm, 1-2-pinnately lobed (ultimate lobes coarsely toothed), faces glabrous. Heads (erect, subsessile) in (leafy) paniculiform to spiciform arrays 12-35(-40) × 2-4 cm (lateral branches relatively short). Involucres globose, 2-4 × (1.5-)2-4 mm. Phyllaries (green) broadly elliptic to obovate, glabrous. Florets: pistillate 6-25; bisexual 15-40; corollas pale yellow, ca. 2 mm, glabrous. Cypselae ellipsoid (4-5-nerved), 0.2-0.9 mm, glabrous. 2n = 18.

Flowering mid summer-late fall. Disturbed habitats, margins of vernal pools, desert flats, usually clay or silty soils; 600-2000 m; Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Utah, Vt., Wash., W.Va., Wis., Wyo.; introduced in Europe, Pacific Islands (New Zealand).

Artemisia biennis is naturalized and weedy in the eastern portion of its range. It is morphologically similar to A. annua, differing primarily in the coarser leaf lobes and larger heads that are sessile in axils of leaflike bracts. Artemisia biennis is considered native to the northwest United States; it may be introduced in other parts of its range. The type specimen is a horticultural specimen from New Zealand.

Coarse, nearly inodorous, glabrous annual or biennial 3-30 dm; lvs 5-15 cm, pinnatisect nearly to the midrib into several narrow lobes that are usually again sharply toothed, or the lower bipinnatifid; infl dense, spike-like or of spiciform branches, the heads usually numerous, crowded, scarcely pedunculate; invol glabrous, 2-3 mm; achenes ellipsoid, 4-5-nerved; 2n=18. Waste places and stream-banks, especially in sandy soil; native to nw. U.S. but widely distributed in our range and elsewhere as a weed. Aug.-Oct.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.

From Flora of Indiana (1940) by Charles C. Deam

Reported from 14 localities within the state and three authors report it as common in waste places. I have found it only five times, and then only a specimen or two at a place.

Indiana Coefficient of Conservatism: C = null, non-native

Wetland Indicator Status: FACW