Genus 97.] 



THISTLE FAMILY, 



2. 



I. Carduus lanceolatus L. Common 

 Bur or Spear Thistle. (Fig. 4058.) 



CardiiHS lanceo/a/us L. Sp. PI. 821. 1753. 



Cirsiunt lanceolatuin Scop. Fl. Cam. Ed. 2, 2: 130. 1772. 



Cnicus lanceolatus Willd. Prodr. Fl. Berol. 259. 1787. 



Biennial; stem stout, branched, more or less 

 tomentose, 3°-5° high, leafy to the heads. Leaves 

 dark green, lanceolate, acuminate, deeply pinnatifid, 

 3'-6' long, or the lowest larger, decurrent on the 

 stem and branches, the lobes triangular-lanceolate, 

 tipped with stout prickles, the margins and decur- 

 rent bases bristly, the upper surface strigose-pubes- 

 cent or hispid, the lower brown-tonientose and mid- 

 nerve pilose especially when young; heads mostly 

 solitary at the ends of the branches, i j4'-2' broad, 

 i'A'-'2' high; bracts of the involucre cottony, nar- 

 row'ly lanceolate, acuminate, all tipped with slen- 

 der erect or ascending prickles; flowers dark purple. 



In fields and waste places. Newfoundland to Georgia, 

 ■west to Minnesota, Nebraska and Missouri. Natural- 

 ized from Europe. Native also of Asia. Other names 

 are Plume, Bank, or Horse Thistle, Bell, Bird, Blue, Button, Bull or Roadside Thistle. July-Nov. 



Carduus altissimus L. Tall or Roadside Thistle. (Fig. 4059.) 



\ ,' Carduus allissimusi,- S>p-'P\.?i2\. 1753. 



Cnicus altissimus Willd, Sp. PI. 3: 1671. 1804. 

 Cirsium altissimuni Spreng, Syst. 3: 373. 1826. 



Biennial or perennial; roots often thickened; 

 stem pubescent, or tomentose, stout, branched, 

 leafy to the heads, 3°-io° high. Leaves ovate- 

 oblong or oblong-lanceolate, sessile, or slightly 

 clasping,sparingly pubescent above, densely white- 

 tomentose beneath, scarcely or not at all decurrent, 

 acute, spinulose-margined, entire, dentate with 

 bristle-pointed teeth or lobed, sometimes pinnati- 

 fid into oblong or triangular-lanceolate segments, 

 the lowest sometimes S' long, narrowed into mar- 

 gined petioles, the uppermost linear or lanceolate, 

 much smaller; heads about 2' broad, ij<'-2' high, 

 mostly solitary at the ends of the branches; outer 

 bracts of the involucre ovate or ovate-lanceolate, 

 firm, with a dark, slightl}' glandular spot at the 

 apex, tipped with short prickles, the inner linear- 

 lanceolate, acuminate, unarmed; flowers light 

 purple. 



In fields and thickets. Massachusetts to Minnesota, 

 Florida, Nebraska and Texas. ,\ug -Sept. 



3. Carduus discolor (Muhl.) Niitt. 

 Field Thistle. (Fig. 4060.) 



Cnicus discolor Muhl.; Willd. Sp. PI. 3: 1670. 

 Carduus discolor Nutt. Gen. 2: 130. 181S. 

 Cirsium discolor Spreng. Syst. 3: 373. 1826. 

 Cnicus altissimus var. discolor A. Gray, Proc. 



Acad. 19: 57. 1883. 



Similar to the preceding fipecies, but lower and 

 more leafy, seldom over 7° high. Leaves deeply 

 pinnatifid into linear, linear-lanceolate, or falcate, 

 prickly toothed segments, white tomentose beneath, 

 sessile, the basal ones sometimes 12' long; heads 

 \Yt'-2' broad, about lYz' high, usually involucrate 

 by the upper leaves, mostly solitary at the ends of 

 the branches; outer bracts of the involucre coria- 

 ceous, ovate, slightly woolly, tipped with slender 

 bristles, which are longer than those of the preced- 

 ing species; inner bracts lanceolate, acuminate, un- 

 armed; flowers light purple or pink, rarely white. 



In fields and along roadsides, Quebec and Ontario to 

 Georgia, Minnesota, Nebraska and Missouri. July-Nov. 



1804. 



V 



Am. _. 



