Leaf blades 2-10 cm × 4-30+ mm. Ray laminae ca. 2 mm. Disc corollas ca. 1.5 mm. Cypselae ca. 2.5 mm. 2n = 22 (as E. alba). Flowering year round, mostly summer-fall. Wet places, often ruderal; 60-1600 m; Ont.; Ala., Ariz., Ark., Calif., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Mex., N.Y., N.C., Ohio, Okla., Pa., S.C., S.Dak., Tenn., Tex., Va., W.Va., Wis.; Mexico; West Indies; Central America; South America; introduced in Europe, Asia, Africa, Pacific Islands, Australia.

Plant: annual, ± strigose throughout; stems 1-10 dm Leaves: simple, opposite, sessile; blades linear, lanceolate, or narrowly elliptic, entire or short-toothed, tip acute INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate, small; peduncles 0-15 mm; involucre 4-10 mm diam; phyllaries 4-5 mm, acute Flowers: Ray flowers: many; corolla 1.5-3 mm, white; ligules short, narrowly linear; Disk flowers: many; corolla 1.5-2 mm, white; style branches very short, included; anthers brown, included Fruit: 1.7-2.2 mm, obovate, smooth or ± warty, glabrous; pappus a crown of minute bristles, < or = 0.2 mm Misc: Damp places; < 300 m; All year References: Kearney & Peebles; Arizona Flora. McDougall; Seed plants of Northern Arizona. ASU specimans