Helianthus nuttallii

Perennials, 100–400 cm (rhizomatous). Stems (usually yellow-brown or greenish, sometimes glaucous) erect, glabrous, hispid, ± hirsute, or scabrous. Leaves cauline; all or mostly opposite to mostly alternate; petioles 0.5–1.5 cm; blades light to dark green, 3-nerved (distal to bases) ± lanceolate to ± ovate, 4–20 × 0.8–4 cm, bases cuneate, margins entire or ± serrate (flat), abaxial faces hispid to hispidulous or tomentulose to villous-tomentose, gland-dotted. Heads 1–6. Peduncles 1–18 cm. Involucres hemispheric, 10–20 mm diam. Phyllaries 30–38 (loose, spreading), lanceolate to lance-ovate, 8–16 × 1.5–3 mm, (margins ciliate) apices acute to acuminate, abaxial faces usually ± strigose, rarely glabrate, not gland-dotted. Paleae 8–12 mm, 3-toothed. Ray florets 10–21; laminae 20–25 mm (abaxial faces not gland-dotted). Disc florets 60+; corollas 5–7 mm, lobes yellow; anthers dark brown to black, appendages yellow. Cypselae 3–5 mm, glabrate; pappi of 2 aristate scales 2.2–4.5 mm plus 0–2 lanceolate scales 0.5–1 mm. 2n = 34 (subspecies unknown).

Distribution

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• Legacy Map

North America.

Discussion

Subspecies 3 (3 in the flora).

Selected References

None.

Lower Taxa

Helianthus nuttallii subsp. nuttallii, Helianthus nuttallii subsp. parishii, Helianthus nuttallii subsp. rydbergii

Key

1	Leaves: abaxial faces tomentulose to villous-tomentose; phyllaries densely hairy (longer hairs 1+ mm)	Helianthus nuttallii subsp. parishii
1	Leaves: abaxial faces hispid to hispidulous; phyllaries ± glabrate (longer hairs 0.5–1 mm).	> 2
2	Plants usually 200–300 cm; leaves mostly alternate, blades narrowly to broadly lanceolate,apices acute to acuminate	Helianthus nuttallii subsp. nuttallii
2	Plants usually 100–250 cm; leaves all or mostly opposite, blades lanceolate to nearly ovate, apices acute to obtuse	Helianthus nuttallii subsp. rydbergii