COMPOSITE. 193 



39f ANTHEMIS. Z,m?t.— Chamomile. 



(Frcan the Greek avQtfiuv, ajlower ; 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. Acheuia 

 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. (T). — 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 chamomile, is said by Nuttall to be naturalized near 

 Lewistown, Del. . Wild or Com 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, 

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

 Pappus none. 



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

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

 Antheniis Cotvla Linn. 



Road sides, &c. Can. ^nd throughout the U. S. June — Oct. (1). — 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; dis^ convex, yellow. Whole plant strongly fetid. An exotic, now al- 

 most everywhere naturalized. . Common May-weed. 



41, PTARMICA. Tourn.—Sneezewort. 

 (From the Greek rrrapnoi, 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. Pursh. Danvers, Mass. Oahes. Aug., Sept 



