Whiteleaf Sunflower

Helianthus glaucophyllus is found in the southern Blue Ridge Province. It is distinguished from H. microcephalus, with which it shares relatively small heads, by glabrous or sparsely scabrous, glaucous leaves. Its closest relative may be H. decapetalus, which has larger heads and, usually, longer phyllaries.

Perennials, 100–200+ cm (rhi-zomatous). Stems erect, glabrous (glaucous). Leaves mostly cauline; opposite (proximal) or alternate; petioles 1–3 cm; blades (light to dark green, abaxially whitish, 3-nerved), lanceolate to lance-ovate, 9–18 × 2.5–7 cm, bases abruptly narrowed, margins serrate, faces glabrous (abaxial) or sparsely scabrous (adaxial), not gland-dotted (abaxial glaucous). Heads 3–15+. Peduncles 0.5–8 cm. Involucres hemispheric, 8–9 mm diam. Phyllaries 12–15, lanceolate to ovate, 8–9 × 1.8–3 mm, (margins ciliate) apices acuminate. Paleae 6.2–7.5 mm, 3-toothed (apices hairy). Ray florets 5–8; laminae 12–14 mm (abaxial faces not gland-dotted). Disc florets 20–35; corollas 5–6 mm, lobes yellow; anthers dark, appendages dark. Cypselae 3.5–3.8 mm, glabrous; pappi of 2 aristate scales 3.2–3.5 mm. 2n = 34.

Helianthus glaucophyllus is a species of sunflower known by the common name whiteleaf sunflower. It is native to the southeastern United States, in the southern Appalachian Mountains in North Carolina, Tennessee, and South Carolina, in and near Great Smoky Mountains National Park.

Helianthus glaucophyllus is a perennial sometimes as much as 200 cm (almost 7 feet) tall, spreading by means of underground rhizomes. Leaves and stems are hairless or almost hairless; leaves appear white on the undersides because of an abundance of wax. One plant can produce 3-15 flower heads, each with 5-8 yellow ray florets surrounding as least 20–35 yellow disc florets. The species grows in open woodlands on hillsides.