632 COMPOSITAE 



2. C. Parthenium (L.) Pers. In waste places: N. S. and Ont., 



to N. J. Native of Europe. 



Locally common as an escape, often wanting. 



C. Balsamita L. has been collected as a waif on L. I. and in Conn., and C. coronarium 

 L. and C. segetum L. have been recorded from near New York. 



42. Matricaria L. 



Rays present, white. 



Achenes obpyramidal. strongly 3-ribbed. I. M. inodora. 



Achenes nearly terete, oblong, faintly 3-5 ribbed. 2. M. Chamomilla. 



Rays none, achenes oblong, faintly nerved. 3. M. matricarioides. 



i. M. inodora L. In fields and waste places: Newf. to N. J. and 

 locally in the interior. Naturalized from Europe. 

 Locally abundant as a weed, often wanting. 



2. M. Chamomilla L. In waste places and on ballast: N. Eng. 



to Pa. Adventive from Europe. 

 Occasional as a weed. 



3. M. matricarioides (Less.) Porter. Adventive eastward from 



the West and the Pacific Coast. 

 Rare as a weed. 

 M. maritima L. has been found as a waif near New York. 



43. Tanacetum [Tourn.] L. 

 1. T. vulgare L. Along roadsides and in fields: N. S. and Ont. 

 to S. Dak., south to N. Car., Mo. and Kan. Native of 

 Europe. 



Common as a weed in most parts of our area. 



44. Artemisia [Tourn.] L. 



Marginal flowers pistillate; central flowers perfect, sterile. I. A. caudata. 



Marginal flowers pistillate; central flowers perfect, fertile. 



Receptacle villous-pubescent. 2. A. Absinthium. 



Rec ptaclc glabrous or sparingly pubescent. 



Leaves dissected, glabrous or pubescent, green, not tomen- 

 tose. 

 Leaves finely 2-3 pinnately divided; heads paniculate. 3. A. annua. 

 Leaves pinnately divided; segments pinnatifid; heads 



in leafy spikes. 4. A. biennis. 



Leaves densely white tomentose, at least beneath. 



Heads 6-8 mm. broad; racemose-glomerate; sea-beach 



plant. 5. A. Stelleriana. 



Heads 2-4 mm. broad, spicate-paniculate or racemose. 



