486 



COMPOS1TAE. 



[Vol. III. 



Y-\ v V'kt V I V I ' - ' I I A 



4. Carduus Virginianus L. Virginia 

 Thistle. (Fig. 4061.) 



Carduus Virginianus L. Sp. PI. 824. 1753. 

 Cirsium Virginianum Michx. Fl. Bor. Am. 2: 90. 



1803. 

 Cnicas Virginianus Pursh, Fl. Am. Sept. 506. 1814. 



Biennial; stem slender, naked or scaly above, 

 pubescent or somewhat tomentose, simple or 

 branched, 2~3 J^ high. Leaves oblong, oblong- 

 lanceolate, or the lowest slightly spatulate, ses- 

 sile, or somewhat clasping, not decurrent, acute 

 or acutish, spinulose-margined, entire, lobed or 

 pinnatifid into triangular-lanceolate lobes, the 

 lower sometimes 8' long and 2 r wide, narrowed 

 into margined petioles, all pubescent or glabrate 

 above, and densely white-tomentose beneath; 

 heads long-peduncled, \ / -\ x / 2 ' broad, about i / 

 high ; outer bracts of the involucre not coriaceous, 

 lanceolate or ovate-lanceolate, tipped with weak 

 short bristles, the inner ones very narrow and 

 merely acuminate; flowers purple. 



In dry woods and thickets, Virginia to Kentucky, 

 Ohio, Florida and Texas. April-Sept. 



5. Carduus Pitched (Torr.) Porter 



Cnicus Pitcheri Torr.; Eaton, Man. Ed. 5, 180. 1829. 

 Cirsium Pitcheri T. & G. Fl. N. A. 2: 456. 1843. 

 Card it its Pitcheri Porter, Mem. Torr. Club, 5: 345. 1894. 



Biennial, persistently white-tomentose throughout; 

 stem stout, leafy up to the heads, usually branched. 

 i-2 high. Leaves sessile, partly clasping, or 

 slightly decurrent, pinnately divided into narrowly 

 linear, entire lobed or pinnatifid, acute sparingly 

 prickly segments i ff -^" wide, with revolute mar- 

 gins; basal leaves often I2 / long; heads solitary or 

 several and racemose-spicate at the ends of the 

 branches, about i^' broad; outer bracts of the in- 

 volucre ovate-lanceolate, sparingly pubescent and 

 tomentose-ciliate, glutinous on the back, tipped 

 with short spreading bristles, the inner narrowly 

 lanceolate, acuminate or sometimes tipped with 

 weak prickles; flowers cream color. 



Shores of Lakes Michigan, Huron and Superior. 

 June-Aug. 



Pitcher's Thistle. (Fig. 4062.) 



Cni 



6. Carduus undulatus Xutt. Wavy- 

 leaved Thistle. (Fig. 4063.) 



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



Cnicus undulatus A.. Gray, Proc. Am. Acad. 10:42. 1874. 



Biennial, persistently and densely white-tomen- 

 tose throughout, or the upper surfaces of the leaves 

 at length green and glabrous; stem stout, leafy, usu- 

 ally branched, i-3 high. Leaves lanceolate or 

 oblong-lanceolate in outline, acute, sessile or decur- 

 rent, or the lowest petioled, undulate, lobed or pin- 

 natifid, the lobes dentate, triangular, often very 

 prickly; basal leaves often 8 / long; heads about 2' 

 broad, and nearly as high, solitary at the ends of 

 the branches; outer bracts of the involucre ovate 

 or ovate- lanceolate, firm, glutinous on the back, 

 tipped with short spreading prickles, the inner 

 ones lanceolate, acuminate; flowers purple or pink. 



On plains and prairies, Lake Huron to the Northwest 

 Territory and British Columbia, south to Kansas, New 

 Mexico and Oregon. June-Sept. 

 Carduus undulatus megacephalus (A. Gray) Porter, Mem. Torr. Club, 5: 345. 1894. 

 cus undulatus var. megacephalus A. Gray, Proc. Am. Acad. 10: 42. 1874. 

 Heads larger than in the type, 2' -3' broad. Minnesota to Idaho and Arizona. 



