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..
H. scabrum Michx. Fl. Bor. Am. 2: 86. 1803.
Stem stout, leafy, mostly hirsute or hispid below and glandular-pubescent above, strict, 1°-4° high. Leaves hirsute, obovate, oblong, or broadly spatulate, 2'-4' long, 1'-2' wide, obtuse at the apex, narrowed to the sessile base or the lowest into margined petioles, denticulate; no tuft of basal leaves at flowering time; heads usually numerous, 6"-8" broad, corymbose- or racemose-paniculate; peduncles stout, densely glandular; involucre 4"-5' high, glandular, its principal bracts in 1 series, linear, acute with a few very small outer ones; flowers yellow; achenes columnar, truncate; pappus brown.
Hieracium Gronovii L. Sp. Pl. 802. 1753.
Stem stiff, mostly slender, leafy and villous or hirsute, at least below, sometimes nearly leafless, 1°-3° high. Leaves villous or hirsute, the basal and lower ones obovate or spatulate, denticulate or entire, obtuse, 2'-6' long, usually narrowed into petioles; stem leaves mostly sessile, oblong or oval, obtuse or acute, narrowed or broad at the base, the upper gradually smaller; heads numerous, racemose-paniculate, 5"-8" broad; peduncles glandular and canescent, slender; involucre about 4" high, somewhat canescent, its principal bracts in 1 series, linear-lanceolate, acute, with several very small outer ones; flowers yellow; achenes spindle-shaped, with a tapering summit; pappus brown.
In dry soil, Massachusetts to Ontario, Illinois, Kansas, Florida, Louisiana and Texas. Santo Domingo. July-Sept. Cat's-ear.
H. marianum Willd. Sp. Pl. 3: 1572. 1804.
Stems usually solitary, slender, pilose-pubescent, at least below, paniculately branched above, 2°-3° high, bearing 2-7 leaves. Basal leaves obovate, oblanceolate or oblong, ascending or erect, obtuse, narrowed at the base, sessile or petioled, hirsute, at least on the veins beneath, entire or glandular-denticulate, 2'-8' long, 1/-2' wide, not purple-veined, mostly glabrous above, those of the stem similar, mostly smaller; heads commonly numerous, corymbose-paniculate, 6"-10" broad, 15-40-flowered, slender-peduncled; peduncles more or less glandular and sometimes canescent; involucre about 4" high, its principal bracts in 1 series, linear-lanceolate, acute, or acuminate, glabrous or nearly so, with a few short outer ones; achenes columnar, truncate; pappus brown, not copious.
In dry woods and thickets, New Hampshire to southern New York, Pennsylvania, Ohio, Kentucky, Alabama and Florida. May-July.
Hieracium alleghaniense Britton, of the mountains of West Virginia, has the stem more abundantly leafy and no tuft of basal leaves at flowering time.