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DescriptionThis perennial wildflower is 2½-5' tall and unbranched, except where the flowerheads occur. The central stem is light green to reddish purple, terete, and more or less covered with either short stiff hairs or longer bristly hairs. Pairs of opposite leaves occur along the central stem; each pair of leaves rotates 90° from an adjacent pair of leaves. There may be 1-2 smaller alternate leaves along the top of the central stem, or along upper lateral stems, underneath the flowerheads. Leaf blades are 2½-6' long and ½-2½' across; they are narrowly lanceolate to ovate in shape and serrated to nearly toothless along their margins. The upper surface of the leaf blades is medium green and rough-textured from minute stiff hairs, while the lower surface is pale green and more or less pubescent. The short petioles are usually ¼-½' long. The central stem and any lateral stems terminate in flowerheads on erect to ascending peduncles (flowering stalks) about 1-4' long. These peduncles have characteristics that are similar to the central stem. Individual flowerheads are 2-3' across, consisting of 10-15 ray florets that surround numerous disk florets. The ray florets have petal-like corollas that are yellow; they are sterile. The disk florets have yellow tubular corollas that are perfect and fertile; they are 5-lobed along their upper rims. Around the base of each flowerhead, there are light green phyllaries (floral bracts) in 3-4 overlapping series; they are narrowly lanceolate to lanceolate in shape and slightly ciliate. When the flowerheads bloom, the phyllaries are ascending to widely spreading. The blooming period occurs from mid-summer to early fall for about 2 months. Afterwards, the disk florets are replaced by achenes about 4 mm. long that are narrowly ovoid, somewhat flattened, and glabrous (hairless). Each achene has a pair of tiny chaffy scales at its apex that become detached easily. The root system is fibrous and long-rhizomatous. This wildflower often forms colonies of plants from the rhizomes.