Helianthus pauciflorus
Gen. N. Amer. Pl. 2: 177. 1818.
Perennials, 50–200 cm (rhizomatous). Stems erect, scabro-hispid. Leaves mostly basal; opposite, or opposite (proximal) and alternate; petioles 0–1 cm; blades lanceovate to oblong-lanceolate, or rhombic-ovate to lance-linear, 5–27 × 2–6 cm, bases cuneate, margins serrate to subentire, abaxial faces sparsely hispid, sparsely, if at all, glanddotted (cauline smaller). Heads 1–10. Peduncles 3–12 cm. Involucres hemispheric, 15–23 mm diam. Phyllaries 25–35, ovate, 6–10 × 3–5 mm, (margins ciliate) apices acute, abaxial faces glabrate to hispid. Paleae 9–10 mm, shallowly 3-toothed to subentire (apices ciliate, hairy). Ray-florets 10–20; laminae 20–35 mm (abaxial faces usually glanddotted). Disc-florets 75+; corollas 6.5–7 mm, lobes usually reddish, sometimes yellow; anthers dark, appendages dark (style-branches yellow). Cypselae 5–6 mm, glabrate; pappi of 2 aristate scales 4.5–5 mm plus 1–4 smaller aristate scales 0.3–2 mm. 2n = 102 (subspecies unknown).
Distribution
Alta., B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask., Ark., Colo., Conn., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Mass., Mich., Minn., Mo., Mont., N.Dak., N.H., N.J., N.Mex., Nebr., Okla., Pa., R.I., S.Dak., Tex., Va., Vt., Wis., Wyo.
Discussion
Subspecies 2 (2 in the flora).
Variation within Helianthus pauciflorus is complex and is complicated by hybridization with H. tuberosus. Hybrids with H. tuberosus are known as H. ×laetiflorus, which is frequently cultivated.
Selected References
None.
Key
| 1 | Plants 80–200 cm; leaves usually alternate distally, blades oblong-lanceolate to lance-ovate, 8–27 cm, apices acuminate | Helianthus pauciflorus subsp. pauciflorus |
| 1 | Plants 50–120 cm; leaves opposite, blades rhombic-ovate to lance-linear, 5–12 cm, apices acute or obtuse | Helianthus pauciflorus subsp. subrhomboideus |