Rayless Sunflower

Perennials, 50–100 cm (with crown buds). Stems erect, distally densely hispid. Leaves mostly basal; opposite; petioles obscure (intergrading with blades); blades obovate to orbiculate, 4.6–14.5 × 2.1–12 cm, bases broadly cuneate to rounded, margins entire or serrulate, abaxial faces strigoso-hispid, not gland-dotted (cauline usually much smaller, alternate distally). Heads usually borne singly. Peduncles 10–20 cm. Involucres shallowly hemispheric, (15–25 ×) 5–8 mm. Phyllaries (often dark purple) 25–33, lanceolate to ovate, 10–14 × 3–5 mm, apices acute to acuminate, abaxial faces hispid or glabrous. Paleae 9–10 mm, subentire to 3-toothed (apices purplish, mucronate). Ray florets 0 or 2–8; laminae (sometimes purplish) 1–2(–10) mm. Disc florets 100–150+; corollas 7–8 mm, lobes reddish; anthers dark, appendages dark. Cypselae 3–4 mm, glabrate; pappi of 2 (often unequal) aristate scales 0.5–2.9 mm. 2n = 34.

Rudbeckia radula Pursh, Fl. Amer. Sept. 2: 575. 1813

Helianthus radula is a North American species of sunflower known by the common name rayless sunflower or pineland sunflower. It is native to the southeastern United States from eastern Louisiana to South Carolina.

Helianthus radula grows in sandy, open woodlands such as pine barrens. It is an perennial herb up to 100 cm (40 inches) tall. One plant usually produces only one flower head, containing 0-8 yellow ray florets surrounding sometimes as many as 150 or more yellow or brown disc florets.