l88 COMPOSITAE 



Family 125. COMPOSITAE Adans. 

 Herbs with iion-stipulate leaves. Flowers on a common receptacle, 

 subtended by an involucre and forming heads. Receptacle naked, chaSy 

 or pitted. Calyx tube nuited with the ovary, its limb obsolete or con- 

 sisting of bristles, scales, etc. Corolla tubular, 5-cleft, that of the margi- 

 nal flowers often expanding into a ray. Stamens five, their anthers 

 syngenesious. Ovary 1-celled, inferior, containing a single erect ovule. 

 Style 2-cleft. 



Flowers all tubular. 

 Receptacle not chaffy or bristly. I. 



Receptacle chaffy or bristly II. 



Some flowers with rays. 



Receptacle not chaffy or bristly. 



Flowers yellow. III. 



Flowers not yellow. IV. 



Receptacle chaffy or bristly. 



Flowers yellow. V. 



Flowers not yellow. VI. 



Involucral bracts in several series. 

 Flowers white or purplish. 

 Flowers all perfect ; bracts not scarious. 

 Heads subtended by sessile bracts. 2. Elkphantopus. 



Heads not subtended by sessile bracts. 

 Aohenes 5 angled, not ribbed. 3. Eupatoridm. 



Achenes 8-10-ribbed. 

 Pappus double, outer shorter than the inner. 



1. Vernonia. 

 Pappus single. 

 Flowers white. 4. Kuhnia 



Flowers rose purple. 5. Lacinaeia. 



Flowers not all perfect ; bracts scarious. 

 Plant dioecious. 15. Antbnnaria. 



Plant not dioecious. 16. Gnaphalium. 



Flowers yellowish. 

 Involucral bracts not glutinous. 

 Heads corymbose. 40. Tanacetum. 



Heads paniculate or spicate-paniculate. 41. Artemisia. 

 Involucral bracts strongly glutinous. 7. Grindblxa. 



Involucral bracts in one series. 

 Vile-smelling plants. 42. Eeechtites. 



Plants without a perceptible odor. 43. Mesadenia. 



II. 



Pappus of 3-6 teeth or awns. 

 Inner involucral bracts separate. 30. Bidens. 



Inner involucral bracts united to middle. 31. Thelesperma. 



Pappus of few-many bristles. 



Plants prickly. 46. Carduus. 



Plants not prickly. 

 Involucre covered with hooked bristles. 45. Arctium. 

 Involucre not covered with bristles. 47. Centaurea. 



