230 COMPOSITE FAMILY. 



6. BUPATORIUM. THOROUGHWOKT, BOXESET. (Dedicated 

 to Eupator MUhridates, who is said to have used the European species 

 in medicine.) 11 Following are the commonest. 



§ 1. lieceplacle flat ; scales of the involucre mostly unequal and more or 

 less imbricated. 



* Leaves 3-6 in a xohorl ; heads b-\5-flowered, cylindriral, the purplish 



scales closely imbricated in several rows ; flowers flesh-colored. 



E. purptireum, Linn. Purpi.e T. or Joe-Pve Weed. Stems simple, 

 3°-12° high, with or without purplish spots or dots ; leaves on petioles, 

 very veiny, oblong-ovate, roughish-toothed and pointed ; corymbs dense, 

 compound. Low grounds. 



* * Leaves alternate or the lower opposite, all long-petioled ; corymbs 

 compound; scales imbricated ; flowers 12-15 in the head, sinall, white. 



E. ser6tinum, Michx. Low grounds from Maryland to Minn, and 

 S., minutely pubescent, tall (3°-6" high), bushy-branched ; leaves ovate- 

 lanceolate and taper-pointed, triple-ribbed, coarsely -toothed, C'-O' long ; 

 the involucre very downy. 



* * * Leaves opposite (or only the uppermost alternate.) and sessile; 



heads corymbed ; the scales more or less imbricated ; flowers white. 



■f- Leaves separate at base; heads mostly 5-8-flowered. 

 ++ Base of leaves broad. 



E. sessilif61ium, Linn. Smooth ; 4°-6° high, with lance-ovate serrate 

 leaves (3'-6' long) tapering from a rounded closely sessile base to a 

 slender point, and small heads (with obtuse scales) in very compound flat 

 corymbs. Mass., S. and W. 



E. rotundifdlium, Linn. Leaves roundish-ovate, blunt, deeply toothed ; 

 heads in a huge and dense corymb, the scales acute. R. 1., S. 



E. teucrif6lium, Willd. Low grounds near the coast ; roughish-pu- 

 bescent; ovate-oblong or lance-oblong, veiny, deeply few-toothed leaves 

 and small corymbs ; scales oblong-lanceolate. 



•M- ++ Base (f leaves narrow. 



E. Alburn, Linn. Roughish-hairy, 2° high ; leaves oblong-lanceolate, 

 coarsely toothed and strongly veiny ; heads crowded in the corymb ; 

 the lanceolate and pointed scales of the involucre white above and larger 

 than the tiowers. Sandy soil, L. I., S. 



E. altisslmum, Linn. Stout and tall, .3°-7° high, downy, with lanceo- 

 late leaves (resembling those of some Goldenrods) tapering to both ends 

 and conspicuously ;5-nerved, either entire or toothed above the middle ; 

 corymbs dense ; scales of the involucre blunt. Penn., W. and S. 



E. hyssopif61ium, Linn. l°-2° high ; smoothish, with narrow linear 

 or lanceolate blunt, l-;}-nerved leaves. Dry sterile soil, from Mass., S. 



■i- -1- Leaves united at base around the stem in pairs (connate-perfoliate). 



E. perfoli^tum, Linn. Thoroughwort or Boneset. Low grounds 

 everywhere (the bitter infusion used as a popular medicine); 2°-4° high, 

 hairy ; the lanceolate leaves taper-pointed, serrate, very veiny, and some- 

 what wrinkled, 5'-8' long ; the very numerous heads crowded in a dense 

 corymb, 10-30-flowered. 



* * * * Leaves opposite, petioled, triple-ribbed; heads in corymbs, 8-30- 

 flowered, the scales of the involucre equal and almost in one row; 

 flowers ichile. 



E. ageratoides, Linn. White Snake Root. Smooth, 2'-'-3° high ; 

 broadly ovate, long-petioled, coarsely and sharply toothed, thin leaves 



