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..
Slender, ashy-gray, 6'-2° high, erect, depressed or sometimes prostrate, finely and densely pubescent. Leaves thick, roughish, the basal and lower ones of the stem oblanceolate or spatulate, petioled, obscurely triple-nerved, obtuse or acutish, crenate-dentate, 3'-6' long, 4"-12" wide; upper leaves gradually smaller, oblanceolate or linear-oblong, acute or acutish, entire; heads 2"-3" high, secund on the spreading or recurving branches of the terminal, usually one-sided panicle; bracts of the involucre linear-oblong; rays 5-9.; achenes pubescent.
In dry soil, Nova Scotia and Quebec to Saskatchewan, Florida, Texas and Arizona. July-Nov.
Solidago pulcherrima A. Nelson (S. longipetiolata Mack. & Bush), of Central North America, ranging eastward into Wisconsin and Missouri, differs mainly by somewhat larger heads, and is here regarded as one of the many races of S. nemoralis Ait.
Solidago mollis Bartl. Ind. Sem. Goett. 5. 1836.
Solidago incana T. & G. Fl. N. A. 2: 221. 1841.
Stem rigid, stout, low, canescent or slightly scabrous, 6'-12' high. Leaves pale, canescent or rough, entire or dentate, strongly 3-nerved, oblong, ovate or oblanceo-late, the lower petioled, 2'-3' long, 3"-12" wide, very obtuse, the upper sessile, smaller; heads 2"-3' high, somewhat or scarcely secund on the short branches of the erect, scarcely one-sided, dense thyrsoid panicle; bracts of the involucre oblong, obtuse or acutish; rays 5-9; achenes pubescent.
Dry plains, Minnesota to Manitoba, Assiniboia, Kansas, Texas and Mexico. July-Sept.
Solidago radula Nutt. Journ. Acad. Phila. 7: 102. 1834.
Stem rough-pubescent, rather slender, 1°-3° high. Leaves thick, green, rough on both sides, the lower oblanceolate or spatulate, dentate-crenate, obtuse or acutish, petioled, 3-8' long, 6"-2o" wide, obscurely 3-nerved, the upper smaller, oblanceolate, entire or nearly so, sessile, distinctly 3-nerved, the uppermost very small; heads 2"-3" high, secund on the short, usually somewhat recurved branches of the dense, often one-sided panicle; bracts of the involucre oblong or linear-oblong, obtuse; rays 3-7, very short; achenes minutely pubescent.
In dry soil, Illinois to Missouri, Louisiana and Texas. Aug.-Sept.