A distinctive goldenrod that likes clearings in the woods or the banks of a stream. Its broad rounded toothy leaves are distinctive, and it takes its common name from the angled stems, which zigzag from one leaf to the next. (“Zigzag” is a technical term in botany.) The flowers grow in a wand at the top of the stem, with more flowers filling in the leaf axils.
Gray gives us a description of the genus Solidago:
SOLIDAGO L. GOLDEN-ROD. Heads few-many-flowered, radiate; the rays 1-16, pistillate. Bracts of the involucre appressed, destitute of herbaceous tips (except nos. 1 and 2). Receptacle small, not chaffy. Achenes many-ribbed, nearly terete; pappus simple, of equal capillary bristles. —Perennial herbs, with mostly wand-like stems and sessile or nearly sessile never heart-shaped stem-leaves. Heads small, racemed or clustered; flowers both of the disk and ray yellow (cream-color in no. 6). Closely related species tending to hybridize freely. (Name from solidare, to join, or make whole, in allusion to reputed vulnerary qualities.)
Gray makes this species part of Solidago latifolia, so we turn to Britton for a description of the species according to current taxonomy (note his use of the technical botanical term we mentioned above):
Solidago flexicaulis L. ZIG-ZAG OR BROAD-LEAVED GOLDENROD. Stem glabrous, angled, usually simple, zig-zag, 3-9 dm. high. Leaves thin, ovate, acuminate at the apex, somewhat pubescent, or glabrous beneath, sharply serrate, 5-17 cm. long, 2-10 cm. wide, the uppermost sometimes lanceolate and entire or nearly so; heads about 6 mm. high; bracts of the involucre obtuse to acutish; achenes hirsute-pubescent. In rich woods, N. B. to Ga., west to S. Dak. and Kans. July-Sept.