Helianthus smithii

Heiser

Rhodora 66: 346. 1964.

Common names: Smith’s sunflower
EndemicConservation concern
Basionym: Helianthus parviflorus var. attenuatus A. Gray in A. Gray et al., Syn. Fl. N. Amer. 1(2): 278. 1884,
Treatment appears in FNA Volume 21. Treatment on page 159. Mentioned on page 141, 145.

Perennials, 70–150 cm (rhizomatous). Stems (usually purplish) erect, glabrous (glaucous). Leaves cauline; opposite (proximal) or alternate; petioles to 1.3 cm; blades (light to dark green, 1-nerved) lance-linear to lanceolate, 7–18 × 1–1.8 cm, bases ± cuneate, margins serrulate, abaxial faces ± hispid, gland-dotted. Heads 1–5. Peduncles 3–6 cm. Involucres hemispheric, 5–15 mm diam. Phyllaries 15–20, lanceolate, 6–9 × 2–2.7 mm, (margins ciliate) apices short-acuminate, abaxial faces glabrous or glabrate, not gland-dotted. Paleae 5.5–6.5 mm, 3-toothed (gland-dotted). Ray florets 6–9; laminae 10–15 mm. Disc florets 25+; corollas 5.5–6 mm, lobes yellow; anthers dark, appendages dark. Cypselae 2.8–3 mm, glabrate; pappi of 2 aristate scales 1.5–2 mm. 2n = 68.


Phenology: Flowering late summer–fall.
Habitat: Dry, open woods
Elevation: 100–300+ m

Discussion

Of conservation concern.

Helianthus smithii is known from relatively few sites. T. A. Storbeck (1984) concluded that it is a distinct species; he could not rule out the possibility that it might be a hybrid of H. microcephalus and H. strumosus. It may also be an extreme variant of H. strumosus that has relatively narrow leaves and small heads.

Selected References

None.

Lower Taxa

None.