178 COMPOSIT.E. 



A stout perennial, 3 to 5 feet high. Leaves large, velvcty-tomeutose 

 heneath, denticulate, the radical ones ovate, tapering to a petiole, the cau- 

 line ones partly clasping. Heads solitary at tln^ summit of corymbose pe- 

 duncles, yellow, appearing late in sunnner. 



JIabilat. — A native of the Eastern Continent, but natiiralized here, 

 growing along roadsides and in waste places. 



.''arf Uficd. — The root — Uiutcd Slalea I'har nacojxria 



Cvnstiluenlx. — A little volatile oil, an acrid resin, a bitter principle, 

 waxy matter, and inulin, the last-named being a substance somewhat re- 

 sembling starch. 



Frcparaliom. — It is generally administered m decoction, though there 

 ai"e commercial extracts, etc. 



Medical Properties and d^ci*. — Elecampane was formerly considered 

 diaphoretic, diuretio^^expoctorant, and emmenagogue, but at present it is 

 little esteemed except among the laity. It is probably stimidant and tonic, 

 and given in hot decoction cajiable of producing some of the effects attrib- 

 uted to it. 



AMBROSIA.— Rao-Weed. 



Character of the Genus. — Sterile and fertile flower's in different heads 

 upon the same plant, the former in spikes or racemes and the latter in the 

 axils of the leaves or at the base of the sterile racemes or si^ilccs. Sterile 

 heads of 5 to 20, funnel-form, staminate flowers ; involucre flattish or top- 

 shai)ed, of 7 to 12 scdes united into a cuj). Fertile flowers : involucre 

 globose-ovoid, oblong or turbinate, closed, pointed, usually armed with 4 

 to 8 tubercles or horns in a single series, 1-flowered. Achenia ovoid ; paj)- 

 pus absent. 



Herbs, or rarely shrubby plants, with opposite or alternate, lobed or 

 dissected leaves, and inconspicuous greenish or yellowish flowai's. 



Ambrosia triflda Linm'. — Gi'eat liag-Weed. 



Description. — Sterile heads in single or panicled racemes or spikes, the 

 involucre regular, 3-ribbed. Fruit with a conical-pointed apex, G-ribbed, 

 the ribs terminating in cristate tubercles. 



Stem stout and hairy, 4 to 12 feet high. Leaves rough and hairy, 

 deeply 3-lobed, the lobes oval-lanceolate, serrate, acuminate. An annual, 

 blooming in August or September. 



Habitat. — In low rich grovmds and along streams from Canada to Geor- 

 gia ;tnd westward. 



Ambrosia artemisiaefoliaLinm'. — Bag-Weed, Hog-Weed. 



Description. — Sterile heads like the preceding, but with the involucre 

 not ribbed. Fertile flowers solitary or clustered toward the base of the sterile 

 spikes or racemes, or in the axils of the upper leaves. Fruit globose or 

 obovoid, nearly glabrous, pointed, armed with G short acute spines or 

 teeth. 



