Helianthus longifolius


Fl. Amer. Sept. 2: 571. 1813.

Common names: Longleaf sunflower
Treatment appears in FNA Volume 21. Treatment on page 156. Mentioned on page 143.

Perennials, 10–30 cm (with crown buds). Stems (green or purplish) erect, glabrous. Leaves mostly basal; opposite; petioles 0–1 cm; blades linear to narrowly obovate, 13–30 × 0.7–2 cm, bases cuneate, margins entire or obscurely serrate, faces glabrous, not gland-dotted (cauline smaller). Heads 3–12. Peduncles 4–11 cm. Involucres hemispheric, 8–12 mm diam. Phyllaries 18–23, linear-linear, 5–11 × 1–2.5 mm, (margins ciliolate) apices ± attenuate, abaxial faces glabrate or glabrous. Paleae 6–8 mm, weakly 3-toothed (apices hairy). Ray florets 8–13; laminae 10–19 mm (abaxial faces not gland-dotted). Disc florets 35+; corollas 4.2–5.5 mm, lobes yellow; anthers dark, appendages dark. Cypselae 2–3 mm, glabrate; pappi of 2 aristate scales 1.4–2.5 mm. 2n = 34.

Phenology: Flowering late summer–fall.
Habitat: Sandstone and granite outcrop edges
Elevation: 100–600 m


Helianthus longifolius is locally escaped from a planting in one county in North Carolina. It is locally abundant where it occurs. It is not similar to or closely related to any other species; natural hybrids of H. longifolius with H. atrorubens and H. occidentalis are known.

Selected References


Lower Taxa