COMPOSiTyE. (co:mi"Ositk family.) 2.j1 



inatc flowers, with slender chaff intermixed, or none. Anthers almost sepa- 

 rate. Fertile involucre (fruit) oblong or top-shaped, closed, pointed, reseml)Iing 

 an adieniuni, and usually with 4-8 tubercles or horns near the top in one row, 

 enclosing a single flower which consists of a- pi>til only ; the elongated branches 

 of the style jirotruding. Achenia ovoid: pappus none. — Homely and coarse 

 weeds, with opposite or alternate lobed or dissected leaves, and incon.^picuous 

 greenish or whitish flowers, produced throughout hue summer and autumn : our 

 species are all annuals. ( 'Afx^poaia, the. food of the gods, an ill-chosen name for 

 these miserable weeds.) 



§ 1. Sterile heads sessile, crowded in a dense njUndiical spike, the top-shnped involucre 

 with its tnmrute nianjin extcndid on one side into a hmje, lanctolule, hooded, re- 

 cnrad, iri:<l/i/-liii/ri/ toolli or appendiuje ; fertile involucre oblong find 4-angled. 



1. A. bidentilta, JMichx. Hairy (1° -3° high), very leafy ; leaves alter- 

 nate, lanceolate, partly clasjting, nearly entire, except a short lobe or tooth on 

 each side near the base. — Prairies of Illinois and southward. 



§ 2. Sterile heads in single or panichd racemes or spikes, the involua-e regidar. 

 * Leaves opjxisite, only once lobed: sterile involuae 3-riljbed on one side. 



2. A. trifida, L. (Gre.vt Ragweed.) Stem stout (40-12° high), rough- 

 hairy, as are the large deeply 3-lobed leaves, the lobes oval-lanceolate and 

 serrate; petioles margined; fruit obovate, 5-6-ribbed and tubercled. — Var. 

 ixtegrif6lia is only a smaller form, with the upper leaves, or all of them, un- 

 divided, ovate or oval. — Moist river-banks : common. 



* * Leaves mani/ of them alternate, all once or twice pinnatlfid. 



3. A. artemisisefdlia, L. (Roman- Woismwood. IIoo-wEEn. Bit- 

 ter-weed.) Much hrauciicd (10-3° high), hairy or r()Ughi>li])ubesceut ; 

 leaves thin, twice-plnnutijid, smoothish above, paler or hoary beneath ; fruit obo- 

 void or globular, armed ivilh almit G short acute teeth or s/>ines. — Waste places 

 everywhere. — An extremely variable weed, with finely cut leaves; rarely the 

 spikes lK*ar all fertile iieads. 



4. A. psilost^chya, T)C. Pani(iilate-l)rauched (2°-:")° high), rough and 

 somewhat hoary with short hispid hairs ; letives once pinnatijid, thidish, the lobes 

 acute, those of the lower leaves often incised ; fruit obovoid, without tuliercles or 

 with verji small ones, pubescent. (A. coronopifoliH, Torr. tj- 6'/-.) — Prairies and 

 plains, Wisconsin, Illinois, and southwestward. 



31. XANTHIUM, Tourn. CocKLEnru. Ci.oxnrR. 



Sterile and fertile Howers occniiying ditVerent heads on the same plant ; the 

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

 volucres anil flowers as in Ambrosia, but the .•;cales separate. Fertile involucre 

 closed, coriaceous, ovoid or oblong, clothed with hooked |)rickles so as to form 

 a rough bur, 2-celled, 2-flowered ; the flowers consisting of a pistil with a slen- 

 der thread-form corolla. Achenia oblong, flat, destitute of pappus. — Coarse 

 and vile weeds, with annual roots, hiw and branching stout stems, and alternate 

 toothed or lol)ed ])etioled leaves ; tlowering in summer and autumn. (Namo 

 from ^dvdos, yellou; in allusion to the color the plants are said to yield.) 



