266 American Midland Naturalist Monograph No. 7 



4. Plants more or less whitish-tomentose; perennials. 

 5. Leaves lanceolate or the upper linear. 



6. Leaves regularly serrate, lanceolate, acuminate, green 

 above, whitish-tomentose beneath; alluvial soil in the 



northern half of the state. Aug. -Sept A. serrata Nutt. 



6. Leaves entire or few-toothed. 



7. Leaves dark green and glabrate above, tomentose be- 

 neath; waste ground, or along railroads, occasional. 



July-Sept A. ludoviciana Nutt. 



7. Leaves whitish- or grayish-tomentose on both sides; 

 along railroads, in waste ground, or sandy soil; more 

 frequent than the preceding. Aug. -Oct. White-sage 



- - A. gnaphalodes Nutt. 



5. Leaves all pinnatifid. 



8. Leaves green and glabrate abo\e, the lobes acute; heads 

 3-4 mm high; receptacle glabrous; waste places, occa- 

 sional: escaped from cult.; nati\e of Eur. July-Oct. 



- -- -- --.. A. vulgaris L. 



8. Leaves canescent on both sides, the lobes obtuse; heads 

 very numerous, about 2 mm high; receptacle hairy; 

 roadsides and waste places, occasional ; escaped from 

 cult.; native of Eur. July-Sept. Common Womiwood or 



Absinth A. absinthium L. 



4. Plants glabrous, annual or biennial. 



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

 biennial ; cultivated ground, waste places, or along rail- 

 roads in the n. half of the state. Aug.-Oct. Biennial Worm- 

 wood A. biennis Willd. 



9. 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 

 49. Cacalia L. — Indian-plantain 



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



woods, local. July-Aug C. siiaveolens L. 



1. Heads 5-flowered; bracts 5. 



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



3. Leaves green on both sides; stem conspicuously grooved; 

 moist ground in woods. July-Sept. [C. reniformis Muhl., 



non Lam.] C. rnuhlenbergii (Sch.-Bip. ) Fern. 



3. Leaves glaucous beneath; stem terete or nearly so; open 



woods. July-Oct C. atriplicifolia L. 



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

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



50. Erechtites Raf. — Fireweed 



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

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



