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Family: Asteraceae
Mid-Atlantic bloom time: April - June
Round-leaved Ragwort produces a cluster of bright yellow composite flowers. Note the difference in leaf shapes between the basal leaves and upper leaves. Upper leaves are more hightly cut and narrower; basal leaves are typically ovate and narrowed to the base (and also toothed).
Compare to the quite similar Golden Ragwort (Packera aurea), particularly noting the difference in shape of the basal leaves.