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..
E. serotinum Michx. Fl. Bor. Am. 2: 100. 1803.
Much branched, finely and densely pubescent, or glabrate below, 4°-8° high. Leaves all slen-der-petioled, lanceolate or ovate-lanceolate, acuminate, sharply serrate, 3'-6' long, ¥-2' wide, 5-nerved at the base, the lower opposite, the upper alternate; heads very numerous, the inflorescence broadly cymose; heads 7-15-flow-ered, 2"-3" high; involucre campanulate, its bracts pubescent, linear-oblong, obtuse or truncate, imbricated in 2 or 3 series, the outer shorter; flowers white.
In moist soil, Delaware to Florida, Minnesota, Iowa, Kansas and Texas. Sept.-Nov.
Slender, puberulent, branched above, 1°-2° high. Leaves opposite, sessile, linear, oblong or oblong-lanceolate, glaucous green, rough on both sides, thick, blunt-pointed, sparingly serrate, or the upper entire, 1'-3' long, 2"s" wide, obscurely 3-nerved and narrowed at the base; inflorescence cymose-paniculate; heads 3"-4" high, about 5-flowered; bracts of the narrow involucre imbricated in about 3 series, white, lanceolate, acute, densely canescent, the outer shorter; flowers white.
In moist places, Massachusetts and Long Island to Florida, Georgia and Louisiana. Aug.-Sept.
Eupatorium album L. Mant. 111. 1767. Eupatorium glandulosum Michx. Fl. Bor. Am. 2:
98. 1803. Eupatorium album subvenosum A. Gray, Syn. FI.
1: Part 2, 98. 1884.
Pubescent with spreading hairs, branched above, 1°-3° high. Leaves opposite, sessile or nearly so, oblong or oblong-lanceolate, obtuse, obtusish or the upper acute at the apex, narrowed at the base, coarsely or rather finely serrate, 1'-4' long, 1/2'-l' wide, rather thick, minutely scabrous above, more or less pubescent beneath; inflorescencecymose-paniculate; heads numerous, 4"-5" long, 5-7-flowered; involucre narrow, its bracts bright white, linear, cuspidate, imbricated in 3-4 series, the outer short and usually pubescent, the inner much longer, glabrous and shining; flowers white.
In sandy soil, Long Island to Florida, Tennessee, Arkansas and Louisiana. Ascends to 3000 ft. in Virginia. Aug.-Sept.
Eupatorium hyssopifolium L. Sp. Pl. 836. 1753. E. linearifolium Walt. Fl. Car. 199. 1788.
Roughish-puberulent, densely corymbosely branched above, bushy, 1°-2° high. Leaves linear, opposite, and fascicled in the axils of the stem, or on short axillary branches, entire or very nearly so, 1/2'-2' long, 1"-2" wide, firm, obtuse at the apex, narrowed at the base; inflorescence densely cymose-paniculate; heads 3 "-4" long, about 5-flowered; involucre campanulate, its bracts linear or linear-oblong, obtuse or truncate, sometime apiculate, puberulent, imbricated in about 3 series, the outer shorter; flowers white.
In dry fields, Massachusetts to Florida and Texas. Justice-weed. Leaf-margins usually revolute. Aug.-Sept. A plant from the coast of Maryland with very narrow leaves, closely approaches Eupatorium lecheae folium Greene, from Florida.