192 COMPOSITE FAMILT. 



24. EUPATbEIUM, THOROtTGHWORT, BONESET. (Old name, 

 dedicated to Eupator Mithridates, who is said to have used the European spe- 

 cies in medicine. Most of the species are American. ) y. 

 E. glechonophyUum, of Chili, and one or two other somewhat woody- 

 stemmed and white-flowered species are cultivated in greenhouses for winter- 

 blooming. — The following are the commonest wild species ; fl. late summer 

 and autumn. 



§ 1. Leaves 3-6 in a whorl: heads b-\5-flawered, cylindrical, the purplish 

 scales closely imbricated in several rows : Jiowers jiesh-colored. 



E. purpttreum, Pukple T. or Joe-Pyb Weed. Low grounds, with 

 simple stems 3° - 1 2° high, with or without purplish spots or dots, very veiny 

 oblong-ovate roughish- toothed and pointed leaves on petioles, and dense com- 

 pound corymbs. 



§ 2.- Leaves opposite (or only the uppermost alternate) and sessile : heads corymbed, 

 the scales more or less imbricated: Jiowers white. 

 * Leaves united at base around the stem in pairs (connate-perfoliate). 

 E. perfoli^tum,-THOEODGHwoRT or BoNESET. Low grounds every- 

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

 lanceolate leaves taper-pointed, serrate, very veiny and somewhat wrinkled, 

 5' - 8' long ; the vei-y numerous heads crowded in a dense corymb, 10 - 30- 

 flowered. 



* « Leaves separate at base : heads mostly 5 - 8-Jlowered. 



E. sessilifblium, on shady banks, is 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 in very compound flat corymbs. 



E. pub6scenSj in dry soil chiefly near the coast, only 2° high, with ovate 

 acute and toothed downy leaves, and 7-8 flowers in the heads. 



E. rotimdifdlium, in similar places and like the foregoing, but with 

 roundish-ovate blunt leaves more deeply toothed, and 5-flowered heads. 



E. teucrifblium, in low grounds near the coast, roughish-pubescent, 

 with ovate-oblong or lance-oblong veiny deeply few-toothed leaves and small 

 corymbs. 



E. dlbum, in sandy soil from New Jersey S., 2° high, is roughish-hairy, 

 with oblong-lanceolate coarsely toothed and strongly veiny leaves, and heads 

 crowded in the corymb, the lanceolate and pointed scales of the involucre white 

 above and larger than the flowers. 



E. altissimum, in dry soil from Penn. to 111. and S., is stout and tall, 

 3° -7° high, downy, with lanceolate leaves (resembling those of some Golden- 

 rods) tapering to both ends and conspicuously 3-nerved, either entire or toothed 

 above the middle ; corymbs dense ; scales of the involucre blunt. 



E. hyssopifdlium, in dry, sterile soil, from Mass. S., l°-2° high, 

 smoothish, wiWi narrow linear or lanceolate blunt 1 - 3-nerve"d leaves. 



§ 3. Leaves alternate or the lower opposite, all. lonrf-petioled : corymbs compound: 

 Jiowers 12-15 in the head, smidl, white. 



E. Ser6tinuin, in low grounds from Maryland to HI. & S., minutely 

 pubescent, tall (3° -6° high), bushy-branched; leaves ovate-lanceolate and 

 taper-pomted, triple-ribbed, coarsely toothed, 5' -6' long; the involucre very 

 downy. ^ 



§ 4. Leaves opposite, petioled, triple-ribbed: heads in corymbs, S-30-flowered, the 

 scales ojtlie involucre eqiuil and almost in one row : Jiowers white. 



E. ageratoldes, White Snake-koot. Common in woods, especially 

 JN., 2 -3° high, smooth, with broadly ovate long-petioled coarsely and sharnlv 

 toothed thin leaves (4' - 5' long), and heads of handsome pure-white flowers in 

 compound corymbs. 



E. arom^tioum, like the preceding, but commoner S. and only near the 

 coast; more slender, usually less smooth, with thicker loaves more bluntlv 

 toothed on short petioles, the corymbs usually less compound. 



