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Upland white goldenrod stems end in a flat-topped panicle 6" across of flowerheads; colonies can present a visually continuous surface of flowers. The flowerheads are 3/4-1" across on 1" stems; each flowerhead has 10-25 white, pistillate ray florets (no stamens) and 30-36 yellowish, perfect disc florets (with both pistils and stamens). The petal-like rays are bright white and spreading, sometimes with notched tips; they look very much like a generic aster flowerhead. The disk florets are dull white and tubular; the five stamens in each disk floret are conjoined and yellow, giving a yellowish cast to the disk. Behind the flowerhead are 4-5 series of hairless bracts (phyllaries), light green at their base, darker green at the tips, each phyllary with a prominent light green mid-vein; the phyllaries are 4 mm long in total. Upland white goldenrod is uncommon in most of northern Illinois except in the sandy soils near Lake Michigan. ITIS and the Flora of North America accept Solidago ptarmicoides as a valid species name; the USDA Plants Database and NatureServe Explorer consider S. ptarmicoides as a junior synonym of Oligoneuron album (as does illinoiswildflowers.info).

Solidago

Solidago ptarmicoides

upland white goldenrod [Blooms: Aug-Sep]