Helianthus laevigatus

Torrey & A. Gray

Fl. N. Amer. 2: 330. 1842.

Common names: Smooth sunflower
Synonyms: Helianthus laevigatus subsp. reindutus E. S. Steele Helianthus reindutus
Treatment appears in FNA Volume 21. Treatment on page 158. Mentioned on page 145, 159.

Perennials, 100–220 cm (rhizomatous). Stems erect, usually glabrous, sometimes proximally hirsute (glaucous). Leaves cauline; opposite (proximal) or alternate; sessile or subsessile; blades (grayish green or bluish green) lanceolate, 8–15 × 1.5–3.5 cm, bases ± cuneate, margins serrate to subentire, abaxial faces glabrous or glabrate (smooth or slightly rough to touch, glaucous). Heads 1–6. Peduncles 2–8 cm. cm. Involucres cylindric, 10–15 mm diam. Phyllaries 23–28, lanceolate, 6–13 × 2–3 mm, (margins sometimes ciliate) apices acuminate, abaxial faces glabrous, not gland-dotted. Paleae 8.5–10 mm, 3-toothed to subentire. Ray florets 5–10; laminae 15–20 mm. Disc florets 35+; corollas 5.5–6.5 mm, lobes yellow; anthers dark, appendages dark. Cypselae 4–5.5 mm, glabrous; pappi of 2 aristate scales 3.2–4.1 mm plus 0–1 deltate scales 0.5–1.1 mm. 2n = 68.

Phenology: Flowering late summer–fall.
Habitat: Shale barrens
Elevation: 300–900+ m


Selected References


Lower Taxa