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DescriptionThis native perennial plant is 3-6' tall. It is largely unbranched below, but forms occasional side stems toward the apex. The stems have indistinct lines of white hairs, and are generally pubescent. The leaves are primarily opposite, although the upper leaves near the inflorescence sometimes alternate. These leaves are up to 7" long and 2½" across, with petioles up to 1" long. They are lanceolate, largely hairless, with coarse serration along the margins, and there are 5 veins that diverge from the base. These leaves tend to nod downward from their petioles, and are often dark green. The flat-topped inflorescence consists of numerous heads of white disk florets; there are no ray florets. Each flowerhead has about 12 disk florets. Each disk floret is about ¼" long, narrow and tubular, with 5 small triangular lobes at the top. There is also a long divided style that is white, which protrudes conspicuously from each floret. The blooming period occurs during late summer or early fall and lasts about a month. There is occasionally a mild floral scent. The small achenes develop flat tufts of hair and are dispersed by the wind. The root system is fibrous and rhizomatous. This plant often forms colonies by means of these rhizomes.