554 



COMPOSITAE. 



VOL. III. 



16. Cirsium palustre (L.) Scop. 

 Fig. 4651. 



Carduus palustris L. Sp. PI. 822. 1753. 



Marsh Thistle. 



Cirsium palustre Scop. Fl. Cam. Ed. 2, 2: 128. 1772. 



Annual or biennial ; stem little branched, 4-5 high, 

 loosely floccose or glabrate and covered by the decur- 

 rent prickly margins of the leaves. Leaves pinnatifid, 

 the lower often 6'-8' long, linear-oblong in outline, the 

 segments lobed, loosely floccose beneath, spinulose; 

 heads usually many, rather less than i' broad, densely 

 clustered, short-peduncled, the involucre ovoid, its bracts 

 with very short, prickly tips. 



Woodlands, East Andover, New Hampshire, recorded as 

 thoroughly naturalized. Native of Europe and northern 

 Asia. Summer. 



Cirsium canum (L.) Bieb., with larger, long-peduncled 

 heads, the decurrent leaf-bases merely ciliate, is recorded as 

 established in Massachusetts. Adventive from Europe. 



105. CARDUUS [Vaill.] L. Sp. PI. 820. 1753. 



Herbs resembling Cirsium in habit, usually annual or biennial, the leaves decurrent on 

 the stem and branches as spiny wings, the heads often nodding. Involucre ovoid to globose, 

 many-flowered, its bracts narrow, in many series. Receptacle copiously bristly, flat or convex. 

 Corolla-tube slender, the limb deeply 5-cleft. Filaments papillose-pubescent. Anthers sagit- 

 tate at the base and with slender auricular appendages. Style-branches obtuse. Achenes 

 mostly obovoid, sometimes angled or ribbed, glabrous. Pappus of many naked or merely 

 roughened bristles. [Ancient Latin name of these plants.] 



About 80 species, natives of the Old World. Type species : Carduus nutans L. 



Heads solitary at end of stem or branches, nodding. i. C. nutans. 



Heads usually several, crowded at ends of winged branches. 2. C. crispus. 



i. Carduus nutans L. Musk Thistle. Plume^ss Thistle. Fig. 4652. 



Carduus nutans L. Sp. PI. 821. 1753. 



Biennial, branched, sparingly tomcntose, 2-3 

 high. Leaves lanceolate in outline, deeply pinnatifid, 

 acuminate, 3'-6' long, the lobes triangular, very 

 prickly; heads long-peduncled, solitary at the end 

 of the stem or branches, \\'-2\' broad, nodding, pur- 

 ple, rarely white, fragrant ; involucre hemispheric, its 

 bracts in many series, lanceolate, long-acuminate, the 

 prominent mid-nerve prolonged into a prickle, or the 

 inner nerveless and awned ; pappus bristles io"-i' 

 long, white, very minutely barbed. 



In waste places, District of Columbia, Pennsylvania 

 and New Jersey to New Brunswick, and in ballast about 

 the seaports. Naturalized or adventive from Europe. 

 Native also of Asia. Bank- or buck-thistle. Queen Ann's- 

 thistle. July-Oct. 



