230 COMPOSITACEAE (COMPOSITE FAMILY) 



ANTHEMEAE (Sagebrush Tribe). — Herbs or shrubs. Heads rayless 

 or radiate; involucre bracts imbricated, not foliaceous, rarely herbaceous, 

 usually dry and scarious; receptacle naked or somewhat chaffy. Anthers 

 not tailed at base. Style branches of the perfect flowers truncate, sometimes 

 obscurely conic-tipped. Pappus none or chaffy or scalelike or crownlike. 



A. Herbs. 

 B. Rays present. 

 C. Rays 4-6, 4-6 mm. long; receptacle chaffy. W. C. E. — Medicinal plant. 

 (Honor of Achilles, who first used it as a vulnerary.) 



Achillea mlllefoUum (yarrow) 

 CC. Rays 10 or more, 10 mm. or more long. 

 D. Receptacle chafify, at least toward its tip. ANTHEMIS (p. 230) . 



DD. Receptacle naked or merely hairy, 

 E. Leaf segments terete or nearly so; receptacle conic. MATRICARIA (p. 230) 

 EE. Leaf segments plainly flat; receptacle flat to hemispheric. 



CHRYSANTHEMUM (p. 231) 

 BB. Rays none. 

 F. Heads sessile in the leaf axils or stem forks. U. — (Perhaps L. solus = alone, 

 vagus = wandering.) Solvla sessilis 



FF. Heads peduncled, either terminal on the branches or clustered. 

 G. Salt-marsh plants; leaves fleshy. COTULA (p- 231) 



GG. Not salt-marsh plants; leaves not fleshy. 

 H. Heads terminal on the leafy branches; receptacle conic. 



MATRICARIA (p. 230) 

 HH. Heads in flat-topped leafless clusters; receptacle flat or hemispheric, 



TANACETUM (p. 231) 



HHH. Heads in bracted spikes or racemes or panicles, not in flat-topped clusters; 



receptacle flat to hemispheric. ARTEMISIA {p. 231) 



AA. Shrubs. ARTEMISIA (p. 231) 



ANTHEMIS (Mayweed) 



Leaves alternate, pinnatifid or dissected. Involucre bracts scarious- 

 margined. Ray flowers white or yellow. Disk flowers yellow. Pappus 

 none or a mere border. — (The Greek name.) 



A. Rays white. 



B. Leaves glabrous, with bad odor; rays neutral. W. E. A. cotula (dog fennel) 



BB. Leaves pubescent, without bad odor; rays fertile. W. E. 



A. arvensis (field mayweed) 

 AA. Rays yePow; leaves somewhat tomentose. W. A. tinctoria (yellow mayweed) 



MATRICARIA (Camomile) 



Herbs, annual. Leaves alternate, 2-3-dissected into narrow or filiform 

 segments. Receptacle naked. Ray flowers white. Disk flowers yellow. 

 Pappus none. — (L. mater = mother, cara = dear; dear to mothers from 

 reputed medicinal properties.) 



A. Heads radiate. 

 B. Rays 20-30; pappus a crown, entire or 4-tootbed; akenes obpyramidal, promi- 

 nently 3-ribbed; herbage nearly odorless. W. E. M.lnodora (scentless camomile 



