342 COMPOSITAB 



55. CENTAUREA L. 



Bracts of tbe involucre fimbriate or lacerate, not spiny. 

 Annual plants ; pappus about the length ot the achene. i. C. Cyanus. 

 Perennial plants : pappus obsolete or short. 

 All flowers perfect, the marginal with scarcely enlarged corollas. 



2. C. nigra. 

 Marginal flowers neutral, with palmately cleft corollas. 3. C. Jacea. 

 Bracts of the involucre tipped with spines. 4. C. Calcitrapa. 



1. Centaurea Cyanus L. Corn Bi<ue-Botti,e. Corn-fi,ower. 

 (Man. p. 1035 ; l.'B.f. 4oy6.) In waste places, escaped from gardens, 

 and in ballast, Quebec to western N. Y. and Va. — Pennsylvania : 

 Northampton ; Philadelphia ; Delaware, Tinicum ; Chester ; 

 Lancaster ; Allegheny. 



2. Centaurea nigra L. Black Knap-weed. Horse- knops. Hard- 

 heads. Centaury. (Man. p. 1035 ■,l.'P.f. 4077.) In waste places and 

 fields, Newf. to Ont. and N. J. Nat. from Eu. — Pennsylvania : Phila- 

 delphia, Fairmount Park. 



3. Centaurea Jacea L. Brown or Rayed Knapweed. (Man. p. 

 1035; I. F.y. 40/8.) In waste places, northern N. Y. and Vt., and in 

 ballast about eastern seaports. Also in B. C. Fug. from Eu. — Penn- 

 sylvania : Philadelphia, waste places. 



4. Centaurea Calcitrapa L. STAR Thistle. (Man. p. 1035 ; 1. V.f. 

 4080.) In waste places and ballast, southern N. Y. and N. J. to Va. Also 

 in B. C. Adv. or nat. from Eu. — Pennsylvania : Bucks; Philadelphia 



56. CNICUS Iv. 



1. Cnicus benedictus L. BlEssed Thistle. Our Lady's Thistle. 



Man. p. 1036 ; I. F. /. 40S/.) In waste places, N. S. to Md., Pa. and 



Ala. and on Pacific coast. Adv. from Eu. — Pennsylvania : Lycoming. 



Summary. 



Orders . . 43 



Families 156 



Genera. . . ■ • 655 



Species . 2,201 



