169.
Erigeron annuus
(Linnaeus) Persoon, Syn. Pl. 2: 431. 1807.
Eastern daisy fleabane, vergerette annuelle
Aster annuus
Linnaeus, Sp. Pl. 2: 875. 1753;
Erigeron annuus
var.
discoideus
(Victorin & J. Rousseau) Cronquist
Annuals,
(10—)60—150 cm; fibrous-rooted or taprooted.
Stems
erect, sparsely piloso-hispid (hairs spreading), sometimes strigose distally, eglandular.
Leaves
basal (usually withering by flowering) and cauline; basal blades mostly lanceolate to oblanceolate or ovate, 15—80 × 3—20 mm, margins coarsely serrate to nearly entire, faces sparsely strigoso-hirsute, eglandular; cauline lanceolate to oblong, little reduced proximal to midstem.
Heads
ca. 5—50+ in loosely paniculiform or corymbiform arrays.
Involucres
3—5 × 6—12 mm.
Phyllaries
in 2—3(—4) series, sparsely villous or hirsuto-villous, minutely glandular.
Ray florets
80—125; corollas white, 4—10 mm, laminae tardily coiling.
Disc corollas
2—2.8 mm.
Cypselae
0.8—1 mm, 2-nerved, faces sparsely strigose;
pappi:
outer minute crowns of setae or narrow scales, inner 0 (rays) or of 8—11 bristles (disc).
2
n
= 27.
Flowering Jun—Aug(—Nov). Mostly open, disturbed habitats, especially roadsides, fields, waste areas; 0—500(—2200) m; St. Pierre and Miquelon; B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Calif., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis.; Mexico (Hidalgo); Central America (Costa Rica, Nicaragua, Panama); Europe; Asia.
Erigeron annuus
is apparently native to eastern North America (United States and southern Canada) and is introduced elsewhere; it probably occurs in North Dakota and Alberta; apparently it has not been documented there. Apparent intermediates between
E. annuus
and
E. strigosus
are encountered.
