Cyclachaena xanthiifolia
Index Seminum (Frankfurt) 1836: 4. 1836.
Leaves: petioles 1–7(–12+) cm; blades 6–12(–20+) × 5–12(–18+) cm. Peduncles 1–6(–12+) mm. Involucres 2–3 mm. Phyllaries: outer 5 ± herbaceous, sericeous to strigillose, inner scarious to membranous, glabrous or glabrate. Paleae 2–2.5 mm. Pistillate florets: corollas 0.1–0.5 mm, or 0. Functionally staminate florets: corollas 2–2.5 mm. Cypselae 2–2.5(–3) mm. 2n = 36.
Phenology: Flowering Jul–Oct.
Habitat: Disturbed sites: abandoned fields, bottomlands, flood plains, stream banks
Elevation: 1–1300 m
Distribution
Alta., B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask., Ariz., Calif., Conn., Colo., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.Dak., Tex., Utah, Vt., Va., Wash., Wis., Wyo.
Discussion
Cyclachaena xanthiifolia is thought to be native to North American prairies and is evidently adventive east of the Mississippi River and in western states. It was recorded once from California as a weed in commercially grown carrots (specimen in CAS).
Selected References
None.