Galinsoga quadriradiata
Syst. Veg. Fl. Peruv. Chil. 1: 198. 1798.
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-lobed 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].
Phenology: Flowering and fruiting summer–fall.
Habitat: Disturbed soils, fields, orchards, gardens, lawns, roadsides
Elevation: 0–2500 m
Distribution
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, in Europe, Asia, Africa, Pacific Islands
Discussion
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.
Selected References
None.