This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", 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..
Epilobium hirsutum L. Sp. Pl. 347. 1753.
Stout, branched, 2°-4° high, softly hirsute-pubescent, spreading by subterranean shoots. Leaves lanceolate or oblong-lanceolate, usually opposite, sessile and often clasping at the base, acute at the apex, sharply serrulate, 1-3' long, 4"-6" wide, thin, pubescent on both sides; flowers axillary, erect, rose-purple, about 1' broad; petals notched, pubescent at the base within; stigma deeply 4-lobed; capsules stalked, 2'-3' long, about 1" thick, pubescent; seeds about i" long, smooth; coma whitish.
In waste places, Maine to central New York, Ontario, and in ballast about the sea-ports. Adventive or naturalized from Europe. English names, codlins-and-cream, fiddle-grass. Apple-, gooseberry- or cherry-pie [smell]. lune-Sept.
Epilobium alpinum L. Sp. Pl. 348. 1753.
E. lactiflorum Haussk. Oest. Bot. Zeit. 29: 89. 1879.
Slender, weak, tufted, glabrous or nearly so, 3'-12' high. Leaves thin, pale, petioled, opposite, or the upper alternate, denticulate or entire, obtuse or obtusish at the apex, narrowed at the base, 6"-2o" long, 2"-8" wide; flowers few, axillary, nearly erect, white or pink, 2."-3" broad, petals notched; stigma nearly entire; capsules slender-stalked, 1'-2' long, about 1/2" thick, glabrous; seeds smooth, narrowed into a beak; coma whitish.
Epilobium anagallidifolium Lam. Encycl. 2: 376. 1786.
Low, usually tufted, 2'-8' high, resembling the preceding species but generally smaller. Stems commonly pubescent in lines and nodding at the apex; leaves oblong or narrowly ovate, entire or nearly so, obtuse at the apex, narrowed at the base into a short petiole, 5"-10" long, 1 1/2"-2 1/2" wide; flowers few, axillary, clustered at the apex, pink or violet-purple, nodding, about 2\" broad; stigma entire; capsule slender-peduncled, glabrous, purplish, about 1' long, i" wide; seeds smooth, short-beaked, about i" long; coma dingy-white.
Labrador, Quebec, and through arctic America to Alaska, south in the Rocky Mountains to Nevada. Recorded from the mountains of New York and New England. Also in Europe and Asia. Summer.