COMPOSITAE 315 



8. SOLIDAGO Iv. 



Heads in short or raceme-like axillary clusters subtended by leaf-like bracts. 

 Stem and branches terete : leaf-blades relatively narrow, shallowly toothed. 



1. S. caesia. 

 Stem and branches angled : leaf-blades relatively broad, deeply toothed. 



2. S.flexicaulis. 

 Heads in a terminal incon.spicuously bracted panicle or thyrsus, or a corymb. 



A. Heads in a terminal panicle or thyrsus ; involucral bracts not ribbed. 

 Tips of the involucral bracts spreading or recurved. 3. >?. sqvarrosa. 

 Tip of the involucral bracts erect or appressed. 

 Panicle or thyrsus nearly equilateral, the branches erect or ascending : 

 heads not secund. 

 Bracts of the involucre decidedly obtuse. 

 Achenes glabrous. 

 Stems copiously pubescent. 

 Ray-flowers with white ligules. 4, S. bicolor. 



Ray-flowers with yellow ligules. 5. 5. hispida. 



Stems glabrous or merely puberulent. ^ 

 Bracts of the involucre i mm. broad at the rounded apex, or more. 

 Involucres 4.5-5.5 mm. high, 3-3.5 mm. thick, the inner bracts 



barely i mm. wide. 6. 5'. erecta. 



Involucres 5.5-6.5 mm. high, 4-4.5 mm. thick, the inner bracts 

 fully I mm. wide. 7. 5. speciosa. 



Bracts of the involucre less than i mm. broad near the somewhat 

 narrowed apex. 8. .?. uliginosa. 



Achenes pubescent. 9. 5. Purshii. 



Bracts of the involucre acute or acutish. 10. S. p-uberula. 



Panicle or thyrsus i-sided, the branches spreading or recurved : heads 

 secund. 

 I,eaf-blades pinnately veined, not 3-ribbed. 

 Plants maritime : leaves fleshy-leathery. 11. 5. sempervirens. 



Plants not maritime : leaves not fleshy-leathery. 

 Internodes of the stem prominently angled below the leaves. 



12. 5. patula. 

 Internodes of the stem terete or essentially so. 

 Stems manifestly pubescent, rarely only in lines. 

 Leaves glabrous ; blades entire. 13. S. odora. 



Leaves pubescent ; blades toothed. 14. 5. rugosa. 



Stems glabrous, at least below the inflorescence. 

 Branches of the inflorescence pubescent. 

 Involucre cylindric, few-flowered. 15. 5. ulmifolia. 



Involucre campanulate, many-flowered. 



16. .S. argula. 

 Branches of the inflorescence glabrous. 

 Involucre less than 5 mm. high. 17. S.juncea. 



Involucre over 5 mm. high. 18. S. neglecta. 



Leaf-blades markedly 3-ribbed. 

 Stem glabrous. I9- -S- serolina. 



Stem pubescent, 

 a. Cauline leaves with relatively long blades, acuminate. 

 Blades of the cauline leaves of a linear type. 



20. ,S. rupestris. 



