This native perennial wildflower is about 2-5' tall. The stems are light green and glabrous (or nearly so). Alternate compound leaves up to 1½' long are located mostly along the lower half of each plant; they are widely spreading. Each compound leaf is odd-pinnate with 7-15 leaflets. The leaflets are about 1-2½" long and a little less than one-half as much across; they are oblong in shape and coarsely serrated along their margins. Some leaflets are a little wider toward their bases than their tips. Upper leaflet surfaces are medium green and glabrous, while their lower surfaces are a slightly lighter shade of green. The leaflets have short petiolules (short slender stalklets) at their bases that connect them to the rachis (central stalk) of the compound leaf. The compound leaves have petioles up to 6" long. Coarsely toothed stipules are located at the bases of the petioles. Upper stems terminate in cylindrical spikes of whitish flowers about 2-8" long and 1" across. The long naked peduncles of the floral spikes are light to medium green and glabrous; they are either unbranched or divide into 2-3 erect stalks, with each stalk bearing a floral spike at its apex. There is a small toothed bract at the base of each division. The flowers are densely packed together all around the central axis of the spike. Each flower consists of a calyx with 4 spreading lobes, 4 long exerted stamens, and a pistil; there are no true petals. The petaloid calyx is greenish white to white and about ¼" across. The stamens (about ½" long) have long white filaments that are very conspicuous. Because of these abundant filaments, the floral spike resembles a white bottlebrush. The blooming period occurs from mid-summer to early fall and lasts about 1-2 months. During the fall, the flowers are replaced by 4-winged capsules that each contain a single seed. These small capsules (about ¼" long) can probably float on water. The root system at the base of the plant is stout and rather woody from its abundant tannins; it usually develops underground runners that form vegetative offsets.