Parasol Whitetop

This perennial wildflower is 2-5' tall and usually unbranched, except where the inflorescence occurs. There are no basal leaves. The terete central stem is light green, purplish red, or yellowish brown; the typical variety is glabrous or sparsely short-pubescent, while var. pubens tends to be more pubescent. Alternate leaves occur along the entire length of the stem; they are ascending and slightly recurved. The lowermost leaves are small and scale-like, while the remaining leaves are 3-5" long, ½-1" across, and relatively uniform in size as they ascend the stem. The leaves are elliptic or lanceolate-elliptic in shape, smooth and short-ciliate along their margins, and either sessile or with short petioles. The upper leaf surface is medium to dark green, while the lower surface is pale green or whitish green. The upper and lower leaf surfaces of the typical variety are glabrous to sparsely short-pubescent. The upper leaf surface of var. pubens is sparsely to moderately short-pubescent or canescent, while the lower surface is moderately to densely short-pubescent or canescent.

The central stem terminates in a flat-headed panicle (compound corymb) of flowerheads about 3-12" across. Individual flowerheads are about ½" across, consisting of 5-12 ray florets that surround 12-25 disk florets. The petal-like corollas of the ray florets are white; the tubular corollas of the disk florets are yellow while in bloom, but become cream-colored or dingy white thereafter. Each disk floret has 5 spreading lobes. At the base of each flowerhead, there are 2-4 series of appressed floral bracts (phyllaries) that are narrowly oblong, green, and glabrous to short-pubescent. The branches of the inflorescence are light green or yellowish brown; they are either glabrous or short-pubescent. Leafy bracts about ½-1½" long occur along these branches; they are lanceolate to narrowly elliptic. The blooming period occurs from late summer into the fall, lasting 1-2 months. Both ray and disk florets are replaced by achenes with whitish tufts of hair. In each tuft of hair, the outermost hairs are bristly and short (less than 1 mm. in length), while the inner hairs are longer (3-6 mm. in length). Individual achenes are about 3 mm. (1/8") long, bullet-shaped, and sparsely short-pubescent. They are distributed by the wind. The root system is fibrous and rhizomatous. Occasionally, small colonies are formed from vegetative offsets.
Distribution Map