COMPOSITE. 211 



S. vertidUatus Mich. : leaves linear, verticillate ; heads few, termi- 

 nal ; pappus campanulate, 5-toothed. 

 . HAB. In shallow water. N. J. to Flor. Aug., Sept. It. Stem 



a foot high, simple. Leaves linear, an inch long, 68 in a whorl. 



Flowers purple. 



50. TANACETUM. Linn. 



Involucre imbricate, hemispherical, scales acuminate. Rays 

 of the corol obsolete, trifid. Receptacle naked. Pappus sub- 

 emarginate. Syngenesia. Superflua. 



T. vulgare Linn.: leaves doubly pinnate, incisely serrate; corymb 

 terminal. 



HAB. Road sides, &c. Aug., Sept. .Zf. Stem 2 4 feet high. 

 Flowers in a dense terminal corymb, yellow. Whole plant 

 odorous. Naturalized. Tansey. 



51. ARTEMISIA. Linn. 



Involucre imbricate ; scales round, connivent. Florets of 

 the ray none. Pappus none. Receptacle naked, or slightly 

 villous. Syngenesia, Superjlua. 



1. A. vulgaris Linn. : leaves tomentose beneath; cauline ones pin- 

 natifid ; segments lanceolate, subdentate, acute ; floral ones undivided, 

 linear, lanceolate ; flowers nearly sessile, oblong, erect ; involucre to- 

 mentose. 



HAB. Banks of streams. Can. and N. S. N. to Arc. Amer. 

 Sept. Nov. 2j..-;Stem% 3 feet high. Flowers few, purplish. 



Mugwort. 



2. A. canadensis Mich.: stem herbaceous and paniculate, mostly erect; 

 radical leaves subpinnate, somewhat tomentose ; cauline subpinnate ; 

 segments subsetaceous, incised, flat, nearly smooth ; flowers partly 

 glomerate and sessile ; involucre subglobose ; scales oval, scarious. 

 A. campestris Pursh. 



HAB. Sandy shores of Lake Erie, &c. . W. to Miss. N. to Hud- 

 son's Bay. July, Aug. 2$.. Stem sometimes decumbent at base, 

 mostly erect, 3 4 feet high. Leaves of linear segments, singly or 

 doubly pinnatifid or subpinnate. Flowers small, very numerous, 

 in terminal panicles resembling spikes. Wild Wormwood. 



3. A. caudata Mich. : stem herbaceous, simple, densely and pyra- 

 midally paniculate; radical and lower cauline leaves sub-bipinnate, 

 pubescent ; upper subpinnate ; segments subsetaceous, alternate, di- 

 varicate, somewhat convex ; flowers pedicillate, erect, globose ovate. 



HAB. Sea shores. N. J. to N. Car. 24!. Stem 2 6 feet high. 



52. CHRYSANTHEMUM. Linn. 



Involucre hemispherical, imbricate ; innermost scales scari- 

 ous. Receptacle naked. Pappus none. 



Syngenesia. Superjlua. 



