Florida Sunflower

Helianthus floridanus is similar to and intergrades with H. angustifolius, which has narrower leaves, and H. simulans, which is more robust and has longer leaves without undulate margins.

Perennials, 100–200 cm (rhizomatous). Stems (green) erect, hispid to hispidulous. Leaves cauline; usually opposite or alternate, rarely whorled; petioles 0–1 cm; blades (1- or 3-nerved) lanceolate to elliptic or lance-ovate, 4–15 × 0.5–6 cm, bases rounded to cuneate, margins entire or serrulate (often undulate, often ± revolute), faces ± scabrous to tomentulose and gland-dotted (abaxial) or scabrous (adaxial). Heads 1–6. Peduncles 2–15 cm. Involucres ± hemispheric, 12–19 × 7–9 mm. Phyllaries 33–38, lanceolate, 5–9 × 1.5–3 mm, apices (at least outer) obtuse, abaxial faces hispidulous to hispid, gland-dotted. Paleae 4.5–6 mm, entire or weakly 3-toothed (apices purplish, glabrate to puberulent, often gland-dotted). Ray florets 10–20; laminae 20–25 mm (abaxial faces gland-dotted). Disc florets 90+; corollas 4–5 mm, lobes usually reddish, sometimes yellow; anthers dark brown or black, appendages dark (style branches yellow). Cypselae 2.5–3 mm, glabrous; pappi of 2 aristate scales 1.5–2.2 mm. 2n = 34.

Helianthus floridanus is a species of sunflower known by the common name Florida sunflower. It is native to the southeastern United States, found in all the coastal states from Alabama to North Carolina, plus Louisiana.

Helianthus floridanus is a perennial sometimes as much as 200 cm (almost 7 feet) tall, spreading by means of underground rhizomes. Leaves are long and narrow, up to 15 cm (6 inches) long. It is a perennial herb sometimes as much as 150 cm (5 feet) tall. One plant can produce as many as 6 flower heads, each with 10-20 yellow ray florets surrounding as least 90 red, purple, or yellow disc florets. The species grows in sandy, open areas at low elevations, often near the coast.