8.
Helenium autumnale
Linnaeus, Sp. Pl. 2: 886. 1753.
Common sneezeweed, hélénie automnale
Helenium autumnale
var.
canaliculatum
(Lamarck) Torrey & A. Gray;
H. autumnale
var.
fylesii
B. Boivin;
H. autumnale
var.
grandiflorum
Torrey & A. Gray;
H.
autumnale
var.
montanum
(Nuttall) Fernald;
H. autumnale
var.
parviflorum
(Nuttall) Fernald;
H. latifolium
Miller;
H. parviflorum
Nuttall
Perennials,
50—130 cm.
Stems
1(—7), branched distally, strongly winged, sparsely to densely hairy proximally, moderately to densely hairy distally.
Leaves
usually moderately to densely hairy, sometimes glabrous; basal blades (withered by flowering) lanceolate, oblanceolate, or obovate, entire or weakly lobed; proximal and mid blades obovate to oblanceolate, usually dentate or entire; distal blades oblanceolate to lanceolate, entire or dentate.
Heads
5—70(—100+) per plant, in paniculiform arrays.
Peduncles
3—10 cm, moderately to densely hairy.
Involucres
globoid, 8—20 × 8—23 mm.
Phyllaries
(connate proximally) moderately to densely hairy.
Ray florets
8—21, pistillate, fertile; corollas yellow, 10—23 × 4—10 mm.
Disc florets
200—400(—800+); corollas yellow proximally, yellow to yellow-brown distally, 2.4—4 mm, lobes 5.
Cypselae
1—2 mm, sparsely to moderately hairy;
pappi
of 5—7 entire, aristate scales (0.5—)0.9—1.5(—1.8) mm.
2
n
= 32, 34, 36.
Flowering (Jul—)Aug—Oct(—Nov). Roadsides, fields, along streams, ditches, seepage areas, around ponds and lakes; 20—2600 m; Alta., B.C., Man., N.W.T., Ont., Que., Sask.; Ala., Ariz., Ark., Calif., Colo., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Miss., Mo., Mont., Nebr., Nev., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., S.C., Tenn., Tex., Utah, Va., Wash., W.Va., Wyo.
