This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
derennial herbs, with alternate punctate resinous-dotted leaves, and discoid heads of white or purplish flowers in terminal cymose corymbs. Involucre turbinate-campanulate, its bracts striate, imbricated in several series, the outer shorter. Corolla regular, the tube slender, the limb 5-lobed. Anthers obtuse and entire at the base, nearly or quite separate. Style-branches slender, obtusish. Achenes 10-striate. Pappus a single row of numerous iery plumose bristles. [Named for Dr. Adam Kuhn, of Philadelphia, a pupil of Linnaeus.]
1. K. eupatorioides.
Pubescent or tomentulose; leaves sharply serrate; heads densely clustered, 6-8 high.
2. K. glutinosa.
Kuhnia eupatorioides L. Sp. Pl. Ed. 2, 1662. 1763.
Eupatorium alternifolium Ard. Spec. Bot. 2: 40. pl. 20. 1764.
Erect, puberulent and resinous, 1°-3° high, branched above. Leaves lanceolate or linear-lanceolate, acute or obtusish at the apex, narrowed at the base, sparingly dentate, or entire, the upper sessile, the lower usually short-petioled; heads several or numerous, peduncled, 4"-5" high, loosely clustered; outer bracts of the involucre lanceolate or ovate-lanceolate, acuminate, the inner much longer, linear, cuspidate; pappus tawny, or sometimes nearly white.
In dry soil, New Jersey to Georgia, Ohio, Minnesota, West Virginia and Texas. Ascends to 3300 ft. in West Virginia. Aug.-Sept.
Kuhnia glutinosa Ell. Bot. S. C. & Ga. 2: 292. 1821-24. Kuhnia suaveolens Fresen. Ind. Sem. Francf. 1838. Kuhnia eupatorioides var. corymbulosa T. & G. Fl. N. A. 2: 78. 1841.
Stouter and often taller than the preceding species, corymbosely or paniculately branched, pubescent or tomentulose, somewhat viscid. Leaves all sessile, lanceolate to ovate-lanceolate, usually sharply serrate with distinct teeth, veiny, 1'-3' long, 3"-10" wide, or those of the branches linear-lanceolate and entire; heads numerous, 6"-8" high, densely clustered in the cymes, their peduncles mostly short; inner bracts of the involucre lanceolate, acuminate; pappus tawny or brown.
In dry soil, Illinois to North Dakota, Colorado, Alabama and Texas. Perhaps a race of the preceding species. Aug.-Oct.
Kuhnia Hitchcockii A. Nelson, a little known species of Kansas, differs by having very small linear leaves, at least on the upper part of the plant.