Maximilian sunflower , hélianthe de Maximilien

Helianthus dalyi Britton

Perennials, 50–300 cm (rhi-zomatous). Stems erect, 5–30 dm, scabrous to scabro-hispidulous. Leaves cauline; mostly alternate; petioles 0–2 cm; blades (light green to gray-green, 1-nerved, conduplicate) lanceolate, 10–30 × 2–5.5 cm, bases cuneate, margins usually entire, sometimes serrulate, abaxial faces scabrous to scabro-hispid, gland-dotted. Heads (1–)3–15 (often in racemiform to spiciform arrays ). Peduncles 1–11 cm. Involucres hemispheric, 13–28 mm diam. Phyllaries 30–40, lanceolate, 14–20 × 2–3 mm, (margins ciliate) apices acute to attenuate, abaxial faces canescent, gland-dotted. Paleae 7–11 mm, entire or 3-toothed (apices greenish, mucronate, hairy). Ray florets 10–25; laminae (15–)25–40 mm. Disc florets 75+; corollas 5–7 mm, lobes yellow; anthers dark brown or black; appendages usually yellow , sometimes partly dark . Cypselae 3–4 mm, glabrate; pappi of 2 aristate scales 3–4.1 mm. 2n = 34.

Flowering late summer–fall. Prairies , fields, waste areas; 0–300(–2100+) m; Alta., B.C., Man., Ont., Que., Sask.; Ala., Ark., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., S.C., S.Dak., Tenn., Tex., Utah, Va., Wash., W.Va., Wis., Wyo.; Mexico.

Helianthus maximiliani is introduced in eastern Ontario and in Quebec. It appears to be native to midcontinental prairie regions and has spread along railroads and highways into all areas of North America. Its wide dispersal may be aided by cultivation for its attractive, showy floral displays. In addition to the usually conduplicate, single-nerved leaves and spikelike arrangement of the heads, it is distinguished by the whitish-canescent indument of the leaves and stems and the long-attenuate phyllaries.