IOWA ACADEMY OF SCIENCES. 225 



heads, with whitish, purple or reddish, usually perfect, 

 rarely dioecious flowers; receptacle flat or somewhat con- 

 vex, bristly. Corolla with a long tube deeply regularily or 

 unequally cleft, stamens with acute anther tips, sagittate 

 at base, filaments usually pubescent, occasionally hairy; 

 style branching, short, with appendage united nearly up to* 

 the obtuse tips, with a hairy ring near the tip, bristles of 

 the pappus connate at the base, usually soft plumose, 

 occasionally bristles of outer flowers barbellate; the tips 

 clavate, achenes oblong, obovate compressed, striated, or 

 obtusely 4-angled, glabrous. 



In the recent revision of the order it has been customary 

 to place Cnicus in with Carduus on the basis of the charac- 

 ters found in the pappus, the pappus of Carduus being 

 merely barbellate. Cirsiurn is retained by Hoffmann in 

 Engler and Prantl. Pflanzenfamilien. In recent studies of 

 many species the writer has found merely barbellate 

 bristles of the outer flowers, but the subtending leaf-like 

 bracts under the involucre is a further distinguishing fea- 

 ture. The inner bracts have more or less bristly append- 

 ages in some of the western species, and in this respect 

 approaches Cfntanrea, although in this genus the pappus 

 consists of aristiform bristles, fimbriolate or of narrow 

 paleae. It seems to me that these genera should be 

 retained. 



Twenty-two species are recorded for oriental Asia by 

 Maximowicz;* and forty-three species for North America, 

 north of New Mexico.f 



According to Bentham and Hooker something like 200 

 species are described, chiefly temperate Europe and Asia 

 and northern Africa and North America, but the number 

 of species has increased somewhat, since the publication of 

 the genera plantarum in 1873. The estimated number 

 now being 250. The total number listed by Heller is 

 seventy-three, whereas in Patterson's check list there are 

 forty-three. It will be seen, therefore, that more than 

 half of the increase in the number of species must be 



♦Bull. Acad. Petersb. 19:489. Mel. Biol. 9: 301. 

 t Gray. Syn. Fl. N. Am. 1 : 398. 



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