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..
Biennial, more or less villous-pubescent; stem stout, simple or branched, leafy, 1°-3° high; roots thick, branched, solid; stem leaves green both sides, sessile and clasping, oblong or oblong-lanceolate in outline, acute, 3'-7' long, 1-2' wide, pinnatifid into triangular, acute, dentate, prickly lobes. Basal leaves petioled; heads solitary, terminal, 2'-3' broad, about 2' high, often involucrate by the upper leaves; outer bracts lanceolate or ovate-lanceolate, with a slight glutinous strip on the back, glabrous or sparingly tomentose, tipped with slender prickles, the inner narrow, long-acuminate; flowers purple, rarely white, fragrant; tips of the pappus bristles usually spatulate.
In fields, Maine to Pennsylvania, Delaware and West Virginia. July-Sept.
Cnicus Hillii Canby, Gard. & For. 4: 101. 1891. Carduus Hillii Porter, Mem. Torr. Club 5: 344. 1894. Cirsium Hillii Fernald, Rhodora 10: 95. 1908.
Perennial, low, villous-pubescent or somewhat woolly; stem leafy, simple or branched, 1°-2° high; root perpendicular, fusiform, slender and hollow above, enlarged below, 8-12' long; leaves green both sides, mostly obtuse, lobed or pinnatifid, the lobes mostly broad and rounded, dentate, spinulose or with some rather stout prickles, the upper oblong, sessile and clasping, the lower spatulate-oblong, narrowed at the base or the lowest ones petioled and 6'-8' long; heads 2'-3' broad, about 2' high; outer bracts of the involucre ovate-lanceolate, tipped with short bristles, conspicuously glutinous on the back, the inner narrowly lanceolate, long-acuminate; flowers purple; pappus bristles slender-pointed or some of them slightly spatulate.
In fields, western Ontario to Minnesota, south to Pennsylvania, Illinois and Iowa. June-July.
Carduus spinosissimus Walt. Fl. Car. 194. 1788. Not Cirsium spinosissimum (L.) Scop. Cirsium horridulum Michx. Fl. Bor. Am. 2: 90. 1803. Cnicus horridulus Pursh, Fl. Am. Sept. 507. 1814.
Biennial or perennial, somewhat woolly when young, but becoming glabrate; stem branched, leafy, 2°-5° high. Leaves green both sides, lanceolate or oblong in outline, sessile and clasping or the basal ones short-petioled and somewhat spatulate, pinnatifid into triangular or broader, spinulose-margined and prickle-tipped, entire or dentate lobes; heads involucrate by the upper leaves, 2'-4' broad, 1 1/2'-2 1/2' high; bracts of the involucre narrowly lanceolate, roughish and ciliate, long-acuminate, unarmed; flowers pale yellow, yellowish, or occasionally purple.
In moist or dry sandy soil, Maine to Pennsylvania, Florida and Texas. Abundant along the edges of salt-meadows in New York and New Jersey. May-Aug., or earlier in the South.