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 millefolium (YARROW) 

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



D. Receptacle chaffy, 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.) Solvia 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 yellow; 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-toothed; akenes obpyramidal, promi- 

 nently 3-ribbed; herbage nearly odorless. W. E. M. inodora (SCENTLESS CAMOMILK 



