55 2 



COMPOSITAE. 



VOL. III. 



j 



10. Cirsium nebraskense Britton. Nebraska 

 Thistle. Fig. 4645. 



Carduus nebraskensis Britton, in Britt. & Brown, 111. Fl. 

 3: 487. 1898. 



Stem densely white-woolly, apparently over i high. 

 Leaves linear-oblong to lanceolate, white-woolly be- 

 neath, green and sparingly loosely woolly above, ir- 

 regularly slightly toothed or entire, the upper 3' -6' 

 long, i'-i' wide, the margins prickly; heads solitary, 

 or few, short-peduncled, about ii' high; outer bracts 

 of the involucre lanceolate, prickle-tipped, the inner 

 narrower with a reflexed acute scarious appendage ; 

 pappus bristles of inner flowers plumose, of the outer 

 barbellate. 



Western Nebraska and Wyoming. Summer. 



ii. Cirsium odoratum (Muhl.) Britton. 



Pasture Thistle. Fragrant Thistle. 



Fig. 4646. 



Cnicus odoratus Muhl. Cat. 70. 1813. 

 Carduus pumilus Nutt. Gen. 2: 130. 1818. 

 Cnicus pumilus Torr. Compend. 282. 1826. 

 Carduus odoratus Porter, Mem. Torr. Club 5 : 345- 

 1894. 



Biennial, more or less villous-pubescent ; stem 

 stout, simple or branched, leafy, i-3 high; roots 

 thick, branched, solid ; stem leaves green both sides, 

 sessile and clasping, oblong or oblong-lanceolate in 

 outline, acute, 3'-?' long, i'-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. 



12. Cirsium Hillii 



m 



2 



(Canby) Fernald. 

 Hill's Thistle. Fig. 4647. 



Cnicus Hillii Canby, Card. & 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, i-2 

 high; root perpendicular, fusiform, slender and 

 hollow above, enlarged below, 8'-i2' long; leaves 

 green both sides, mostly obtuse, lobed or pin- 

 natifid, the lobes mostly broad and rounded, den- 

 tate, 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 invo- 

 lucre ovate-lanceolate, tipped with short bristles, 

 conspicuously glutinous on the back, the inner 

 narrowly lanceolate, long-acuminate ; flowers pur- 

 ple ; pappus bristles slender-pointed or some of 

 them slightly spatulate. 



In fields, western Ontario to Minnesota, south to 

 Pennsylvania, Illinois and Iowa. June-July. 



