Helianthus decapetalus L.
Family: Asteraceae
forest sunflower, pale sunflower, thin-leaved sunflower
[Helianthus scrophulariifolius Britton,  more...]
Helianthus decapetalus image
from USDA Plants website  
Helianthus decapetalus image
Etymology: Helianthus: derived from two Greek words helios, "sun," and anthos, "flower," in reference to the sunflower's supposed tendency to always turn toward the sun
Plants: erect, perennial, 2'-5' tall forb; stems smooth below the hairy inflorescence
Leaves: opposite along lower stem, upper becoming alternate, widely oval to lance-like, often 1 1/2" wide, quickly tapering to the stalk, thin, pale below, sharply toothed
Flowers: head 1 1/2"-4" wide with 8-15 yellow rays and a yellow, 3/4" wide disk; inflorescence one to a few heads on long stalks, bracts (phyllaries) usually longer than the disk, pointed, leaf-like, slightly spreading; blooms Aug.-Oct.
Habitat: woods, streambanks
Conservation Status: Native