Jones: Flora of Illinois, 152. Compositae 267 



4. Plants glabrous, annual or biennial. 



8. Heads 2-3 mm. high; leaf-divisions laciniate-dentate; plants biennial; 



cult, ground, waste places, or along railroads, in the n. half of the 



state. Aug. -Oct. Biennial Wormwood A. biennis Willd. 



8. Heads 1.5-2 mm. high; leaf-segments 1-3 mm. long; plants annual; 



roadsides and waste places, occasional; nat. from Eur. Aug. -Oct. 



Annual Wormwood A. annua L. 



Tribe 10. Senecioneae 

 45. Cacalia L. — Indian-plantain 



(Mesadenia Raf.) 



1. Heads 20-30-flowered; bracts 12-15; receptacle flat; leaves hastate, dentate; 



woods, local. July-Aug. [Synosma suaveolens (L.) Britt.} 



C. suaveolens L. 



1. Heads 5-flowered; bracts 5; receptacle raised in the center to a conical point. 

 2. Leaves thin, reniform or flabellate, lobed or sinuately dentate. 



3. Leaves green on both sides; stem grooved; woods. July-Sept. [C. reni- 



formis Muhl.} C. muhlenbergii (Sch.-Bip.) Fern. 



3. Leaves glaucous beneath; stem terete; open woods. July-Sept 



C. atiiplicijolia L. 



2. Leaves thick, oval, entire or denticulate, green on both sides; wet marly 

 soil, local. June-Aug C. tuberosa Nutt. 



46. Erechtites Raf. 



E. hieracijolid (L.) Raf. Fireweed. In moist woods, recently burned clear- 

 ings, along roads, or in bogs, local. Aug.-Oct. 



47. Senecio L. — Ragwort 



1. Basal leaves dentate or entire, the median stem-leaves often pinnatifid; 

 plants perennial. 

 2. None of the leaves cordate; basal leaves obovate or elliptical. 



3. Leaves and stems more or less floccose, tardily glabrate; involucre 

 5-7 mm. high; achenes hispidulous on the angles; prairie soil, and 



in dry ground in oak woods, local. May-June S. plattensis Nutt. 



3. Leaves glabrous or nearly so; stem glabrous, or slightly floccose when 

 young; involucre 4-5 mm. high. 

 4. Basal leaves obovate or suborbicular; achenes glabrous; bluffs and 

 open woods, not common. Apr.-June. {_S. rotundus (Britt.) 



Small} S. obovatus Muhl. 



4. Basal leaves oblanceolate; achenes often hispidulous on the margins; 



roadsides and open woods. May-June. [5. balsamitae Muhl.} 



S. pauperculus Michx. 



2. Basal leaves more or less cordate or subcordate, long-petioled, mostly 



glabrous; wet ground. Apr.-June. \_S. semicordatus Mack. & Bush} 



..S. aureus L. 



