Helianthus divaricatus L.

One of the earlier flowering perennial Helianthus, H. divaricatus resembles the tetraploid H. hirsutus but differs by its usually glabrous and often glaucous stems, sessile or subsessile leaves, and smaller reproductive organs (disc corollas, paleae, cypselae). Plants from the Ozark region of Arkansas have larger leaves and heads and may represent a polyploid form of H. divaricatus. Natural hybrids with H. microcephalus have been named H. glaucus Small (D. M. Smith and A. T. Guard 1958). Hybrids with other species differ from H. divaricatus in having short but distinct petioles, hairy stems, leaves with more rounded bases, and primary lateral leaf veins diverging in a subopposite manner distal to bases, rather than being strictly opposite and basal.

Perennials, 20–150 cm (rhizomatous) . Stems erect, usually glabrous , rarely ± hairy (often glaucous). Leaves cauline; opposite; sessile; blades (light to dark green, sometimes whitish abaxially, 3-nerved at bases) lanceolate to lance-ovate, 6–15 × 1–5 cm, bases rounded to cordate, margins subentire to serrate, abaxial faces sparsely hispid to hispidulous, gland-dotted. Heads 1–10. Peduncles 0.5–9 cm. Involucres hemispheric, 10–15 mm diam. Phyllaries 18–25, lanceolate, lance-linear, or lance-ovate, 6–12 × 2–2.5 mm, (margins ciliate) apices acuminate to attenuate, abaxial faces hispidulous to glabrate, not gland-dotted. Paleae 5–8 mm, 3-toothed (apices ciliate). Ray florets 8–12; laminae 15–30 mm. Disc florets 40+; corollas 4.2–5.5 mm, lobes yellow; anthers usually dark brown to black, appendages yellow. Cypselae 3–3.6 mm, glabrate; pappi of 2 aristate scales 2.2–2.5 mm. 2n = 34.

Helianthus divaricatus var. angustifolius Kuntze

Chile Central

This plant attracts birds. (NPIN, 2009)

This plant is listed by the U.S. federal government or a state. Common names are from state and federal lists. In Rhode Island woodland sunflower is listed as Special Concern. (USDA PLANTS, 2009)

Blooming occurs July-October. (Hultman, 1978) The plant blooms July-September. (UW, 2009)

USA: AL , AR , CT , DE , FL , GA , IL , IN , IA , KY , LA , ME , MD , MA , MI , MS , MO , NH , NJ , NY , NC , OH , OK , PA , RI , SC , TN , VT , VA , WV , WI , DC (NPIN, 2009)

Canada: ON , QC (NPIN, 2009)

USDA Native Status: L48(N), CAN(N) (NPIN, 2009)

Habitat is dry thickets and open woods. (Hultman, 1978) Native habitat comprises woodland, savannah, and rocky bluff. (NPIN, 2009) This plant inhabits dry woods and open places. (UW, 2009)

This is a perennial. (NPIN, 2009)

Overall This is an erect plant. (UW, 2009)

Flowers are yellow. This is a daisy-like flower is made up of many petal-like rays. (Hultman, 1978) Flowers have 8-15 yellow rays and a yellow disk. Inflorescence (cymose) one to several heads at the ends of the stiff branches, bracts (phyllaries) loosely arranged and often with reflexed tips. (UW, 2009)

Fruit is a capsule. (NPIN, 2009)

Leaves Thick, slender leaves are rough on top and hairy underneath. They are attached in pairs by short stalks. (Hultman, 1978) Leaves are all opposite and usually stalkless or on a very short stalk. They are rough above, sparsely hairy below, and narrowly to widely lance-like. The base is straight to broadly rounded, and the leaf ends in a sharp tip. (UW, 2009)

Stems are smooth. (Hultman, 1978) Stems are smooth below the inflorescence. (NPIN, 2009)

Plant is 2-6.5' tall. (Hultman, 1978) The plant is 20"-60" tall. (UW, 2009)

Flowers head is 1 1/2"-3" wide. (UW, 2009)

Helianthus divaricatus, commonly known as the rough sunflower, woodland sunflower, or rough woodland sunflower, is a North American species perennial herb in the family Asteraceae. It is native to central and eastern North America, from Ontario and Quebec in the north, south to Florida and Louisiana and west to Oklahoma and Iowa.

Helanthus divaricatus commonly occurs in dry, relatively open sites. The showy yellow flowers emerge in summer through early fall.

The woodland sunflower is similar to Helianthus hirsutus, but its stem is rough. It is up to 1.5 m tall with short stalked, lanceolate to oval leaves, 1–8 cm wide with toothed margins. Its flowers have 8 to 15 rays, each 1.5 to 3 cm (0.6-1.2 inches) long, surrounding an orange or yellowish brown central disk. The plant attracts birds and butterflies. The Latin specific epithet divaricatus means spreading in a straggling manner.

Helianthus divaricatus là một loài thực vật có hoa trong họ Cúc. Loài này được L. mô tả khoa học đầu tiên năm 1753.