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..
Herbaceous twining vines, or some tropical species erect shrubs, with opposite, petioled leaves, and discoid, mostly cymose-paniculate heads of whitish flowers. Heads 4-flowered.
Involucre oblong, of 4 slightly unequal narrow bracts. Receptacle small, naked. Corolla regular, its tube slender, the limb campanulate, 5-cleft. Anthers entire and obtuse at the base. Style-branches elongated, acutish. Achenes truncate, 5-angled. Pappus of numerous capillary bristles. [In honor of Joseph Gottfried Mikan, 1743-1814, professor at Prague.]
About 150 species, natives of America. Besides the following, two others occur in the southern United States. Type species: Mikania hastata (L.) Willd.
Eupatorium scandens L. Sp. Pl. 836. 1753. M. scandens Willd. Sp. Pl. 3: 1743- 1804. Willoughbya scandens Kuntze, Rev. Gen. Pl. 371. 1891.
Glabrous or nearly so, twining over bushes, 5°-15° long. Leaves ovate or hastate, deeply cordate at the base with the lobes rounded or truncate, acuminate at the apex, repand or obtusely dentate, 2'-4' long, 1'-2' wide; petioles slender, shorter than the blades; heads in compound clusters borne at the ends of the branches; involucre about 3" long, its bracts acuminate or apiculate; flowers white or pink; achenes resinous.
In swamps and moist soil, Maine to western Ontario, Florida and Texas. West Indies and South America. July-Sept.