Plants 8-62 cm. Leaf blades 20-60 × 15-45 mm. Peduncles 5-20 mm. Involucres hemispheric to campanulate, 3-6 mm diam. Phyllaries falling. Paleae: outer falling, broadly elliptic to obovate, 2-3 mm; inner falling, linear to lanceolate, 2-3 mm, entire or 2- or 3-lobed, lobes to 1/3 total lengths, blunt. Ray florets (4-)5(-8); corollas usually white, sometimes pink, laminae 0.9-2.5 × 0.9-2 mm. Disc florets 15-35. Cypselae: rays 1.5-2 mm; discs 1.3-1.8 mm; pappi: rays of 6-15 fimbriate scales 0.5-1 mm; discs 0, or of usually 14-20, rarely 1-5, white, lanceolate to oblanceolate, fimbriate, sometimes aristate, scales 0.2-1.7 mm. 2n = 32 [48, 64]. Flowering and fruiting summer-fall. Disturbed soils, fields, orchards, gardens, lawns, roadsides; 0-2500 m; introduced; Alta., B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Colo., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., Wash., W.Va., Wis.; Mexico; West Indies; Central America; South America; introduced in Europe; Asia; Africa; Pacific Islands. Tetraploids of Galinsoga quadriradiata are native to Mexico. Higher polyploids are found in South America and differ from the tetraploids by their coarsely crenate-serrate leaves, cylindro-campanulate involucres, and usually reddish purple limbs of ray corollas that extend at right angles to involucres.
Freely branching, somewhat hairy, 2-7 dm, the hairs of the stem generally fairly coarse and spreading; lvs petiolate, with ovate (often broadly so), rather coarsely toothed blade 2.5-7 נ1.5-5 cm; heads mostly rather numerous (in well developed plants) in open, leafy cymes, slender-pedunculate, the peduncles and often also the invols spreading-villous, with gland-tipped hairs; outer invol bracts 1-2, herbaceous, deciduous, the inner 3-4 mm, deciduous with their attached receptacular bracts; rays (3-)5(6), white (pink), strongly 3-toothed, 2-3 mm, nearly as wide; inner receptacular bracts mostly entire; disk 3-6 mm wide; achenes black, hispidulous with appressed or ascending hairs; pappus of the disk of slender, fimbriate scales tapering to a short but definite awn-tip, often shorter than the cor, that of the rays of short but well developed fimbriate scales, about equaling the tube; 2n=32, 48, 64. Native of C. and S. Amer., now a cosmopolitan weed. June-Nov. (G. bicolorata and G. caracasana, with pink rays; G. ciliata)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.