"212 COMPOSITE. (COMPOSITE FAMILY.) 



scctL-d leaves, and inconspicuous greenish or whitish flcnrcrs. ('A/i/?po<na, tfa 

 fowl of the yods, an ill-chosen name for these worthless ami coarse weeds.) 



$ 1. Sterile heads sessile, crowded in a dense cylindrical spike, the top-shaped involucre 

 with the truncate mart/in extended on one side into a larye, lanceolate, hooded, 

 recurved, bristly-hairy tooth or appendage ; fertile involucre oblong and 4-anf/k-d. 



1. A. bidClltfita, Michx. Hairy (l-3 high), very leafy; leaves al- 

 ternate, lanceolate, partly clasping, nearly entire, except a short lobe or tooth 

 on euch side near the base. Qp Prairies of Illinois and southward. Aug. 



$ 2. Sterile heads in sinyle or panicled racemes or spikes, the involucre regular. 

 * Leaves opposite, only lobcd : sterile involucre 3-ribbcd on one side. 



2. A. trifida, L. (GREAT RAGWEED.) Stem square, stout (4-12 u 

 high), rough-hairy, as are the large deeply 3-lobed leaves, the lobes oval-lanceo- 

 late and serrate ; petioles margined ; fruit obovatc, G-ribbed and tuberclcd. (j) 

 Var. INTEGUIF6LIA is only a smaller form, with the upper leaves or all of 

 them undivided, ovate or oval. Moist river-banks ; common. Aug. 



# * Leaves many of them alternate, once or twice pinnatijid. 



3. A. arte in isiae folia, L. (ROMAN WORMWOOD. HOG-WEED. BIT- 

 TER-WEED.) Much branched (l-3 high), hairy or roughish-pubescent ; 

 leaves thin, tivice-pinnat/Jid, smoothish above, paler or hoary beneath ; fruit obo- 

 void or globular, armed with about 6 short acute teeth or spines. (1 Waste 

 places everywhere. July - Sept. An extremely variable weed, with finely 

 cut leaves, embracing several nominal species. 



4. A. psilostacliya, DC. Paniculate-branched (2 -5 high), rough 

 and somewhat hoary with short hispid hairs ; leaves once pinnate/id, thickish, the 

 lobes acute, those of the lower leaves often incised ; fruit obovoid, without tuber- 

 cles or with very small ones, pubescent, (i) (A. coronopifolia, Torr. $- Gr.) 

 Prairies and plains, Illinois and south westward. Aug. 



31. XANTHIUM, Tourn. COCKLEBCR. CLOTBUR. 



Sterile and fertile flowers occupying different heads on the same plant ; the 

 latter clustered below, the former in short spikes or racemes above. Sterile 

 involucres and flowers as in Ambrosia, but the scales separate. Fertile invo- 

 lucre closed, coriaceous, ovoid or oblong, clothed with hooked prickles so as to 

 form a rough bur, 2-ccllcd, 2-flowcrcd; the flowers consisting of a pistil with a 

 slender thread-form corolla. Achenia Oblong, flat ; destitute of pappus. 

 Coarse and vile weeds, with annual roots, low and branching stout stems, and 

 alternate toothed or lobcd pctioled leaves. (Name from v$or, yellow, in allu 

 sion to the color the plants arc said to yield.) 



1. X. strum a rill ill, L. (COMMON COCKLEBUR.) Rough; stems itn- 



innrd ; /ra/vs di/nfi'il-friii>i(/ul"r and mure or A'.ss heart-doped, on long petioles, 

 toothed and cut or obscurely lobcd; fruit oval or oblong (i '-' long), pubes- 

 cent on the lower part of and between the hooked prickles, and with two strong 

 and usually straight ImiL-s at the summit. l>ani-yards, &c. (Nat. from Ku ) 

 \!" " -|M.u,..| -,\, M | nt'fi-n larrcr frnit ($'-'' ' 



