COMPOSITE 193 



39. ANTHEMIS. Linn. Chamomile. 



(From the Greek ai>Qcjnuv, a flowery on account of the profusion of its blos- 

 soms.) 



Heads many-flowered ; the ray flowers in one series, ligulate, 

 pistillate ; those of the disk tubular, perfect. Scales of the in- 

 volucre imbricate, in a few series. Receptacle convex, oblong 

 or conic, with membraceous chaff among the flowers. Achenia 

 terete or obtusely 4-angled, striate or smooth. Pappus none 

 or a membranous margin. 



A. arvensis Linn. : diffuse, pubescent ; leaves pinnately parted ; the lobes 

 linear-lanceolate, with very acute teeth ; heads solitary at the summits of 

 the leafless branches ; receptacle conic ; the chaff lanceolate, acuminate. 



Fields and cultivated grounds. N. Y. to Virg. June Aug. (J). Stem 

 9 15 inches high, branched. Leaves grayish-pubescent. Heads large; rays 

 broad, white, spreading ; disk yellow, convex. Introduced from Europe. A. 

 nobilis Linn., the common chamamile, is said by Nuttall to be naturalized near 

 Lewistown, Del. Wild or Corn Chamomile. 



40. MARUTA. Cass. May Weed. 

 (Origin not known.) 



Heads many-flowered ; the ray flowers ligulate, neutral ; 

 those of the disk perfect. Involucre hemispheric, in a few 

 series, shorter than the disk. Receptacle conic or convex, 

 chaffy throughout or only at the top. Achenia ribbed, smooth. 

 Pappus none. 



M. Cotula D. C. : smoothish ; leaves bi-pinnatifid, the segments subulate- 

 linear; receptacle conic, with narrow acuminate chaff at the summit. 

 Anthemis Cotula Linn. 



Road sides, &c. Can. and throughout the U. S. June Oct. . Stem 

 a foot high, erect, branched. Leaves pale green, more or less pilose ; the seg- 

 ments very narrow. Heads on elongated slender peduncles ; rays about 12, 

 white; disk convex, yellow. Whole plant strongly fetid. An exotic, now al- 

 most everywhere naturalized. Common May-weed. 



41. PTARMICA. Tourn. Sneezewort. 



(From the Greek rrrappos, in allusion to its effect upon the nostrils.) 

 Involucre campanulate ; the scales scarious' on the margin. 

 Receptacle flat or scarcely convex, broad, chaffy. Rays 5 20, 

 flat, spreading much longer than the involucre. Achenia ob- 

 compressed, the outer ones often somewhat winged on the 

 margin. 



P. vulgaris D.C.: stem erect, branching above; leaves smooth, sessile, 

 linear-lanceolate, acuminate, coarsely and equally serrate ; chaff of the re- 

 ceptacle oblong, pubescent. Achillea Ptarmica Linn. 

 Dry swamps. Can. to N. Y. Pufsh. Danvers, Mass. Oakes. Aug., Sept 



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