252 American Midland Naturalist Monograph No. 2 



2. Heads in dense terminal compound corymbiform cymes (Oltgoneuron 

 Small). 

 17. Leaves oval or elliptical, scabrous on both sides, crenate; stem pubes- 

 cent or puberulent throughout; prairie soil, mostly along roads, 

 throughout 111., except the s. counties. Aug. -Sept. Rigid Goldenrod 



S. rigida L. 



17. Leaves lanceolate or linear, glabrous; stem glabrous, or puberulent 

 above. 

 18. Inflorescence pubescent or puberulent; stem leaves entire, recurved, 

 somewhat conduplicate, sheathing at the base; moist ground. 



Aug.-Sept. Riddell Goldenrod S. riddellii Frank 



18. Inflorescence, as well as the rest of the plant, glabrous; leaves flat; 



moist ground. Aug.-Sept. Ohio Goldenrod 



- S. ohioensis Riddell 



1. Heads sessile or subsessile, in flat-topped corymbs; ray- flowers more numer- 

 ous than the disk-flowers; receptacle fimbriolate; leaves punctate (Eu- 

 thamia Nutt.). 

 19. Stem, leaves, and peduncles hirtellous; leaves distinctly 3-5-veined; moist 



ground. Aug. -Oct. [S. graminijolia var. nuttallii (Greene) Fern.] 



S. hirtella (Greene) Bush 



19. Stem glabrous; leaves glabrous, 1 -veined or obscurely 3-veined, the mar- 

 gins scaberulous. 



20. Heads sessile, 3-7 in each glomerule; moist soil. Aug. -Oct 



S. media (Greene) Bush 



20. Heads nearly all shortly pedicellate, usually solitary; prairie soil, n. 

 III., not common. Aug.-Sept S. remota (Greene) Friesner 



13. BoLTONiA L'Her. 



1. Leaves lanceolate to oblanceolate, 0.5-2 cm. wide, the upper smaller; disk 

 5-8 mm. broad; alluvial soil, river banks, or wet ground in woods, locally 

 throughout 111. Aug. -Oct B. asteroides (L.) L'Her. 



1. Leaves linear, 1-5 mm. wide, those of the branchlets subulate; disk 3-5 mm. 

 broad; dry soil, s. 111., rare; St. Clair Co., Breiidel; Jackson, Marion, and 

 Washington counties, Vasey B. diffusa Ell. 



14. Aster L. — Aster 



1. Lower leaves cordate or subcordate, long-petioled, serrate. 



2. Upper leaves cordate-clasping; stem pubescent, divaricately branched 

 above; heads numerous; involucres 5 mm. high; bracts pubescent, green- 

 tipped; rays 8-15, pale blue or violet, 6-10 mm. long; dry soil, open 



woods and thickets, rare. Sept. -Oct A. undidatus L. 



2. Leaves not clasping. 



3. Involucral bracts and peduncles glancular-pubcrulent; rays 12-16, pale 

 purple, 10-14 mm. long; bracts green-tipped; open woods, in the n. 



half of 111. Aug.-Sept. Large-leaved Aster A. macrophyllns L. 



3. Involucres and peduncles not glandular. 



4. Bracts of the involucre puberulent or pubescent. 



