COMPOSITAE 315 



8. SOLIDAGO L. 



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

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



1. 5". caesia. 

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



2. S.flexicaulis. 

 Heads in a terminal inconspicuously 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. S. sqttarrosa. 

 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. 



Raj'-flowers with white ligules. 4. 5. bicolor. 



Ray-flowers with yellow ligules. 5. S. 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. S. erecta. 



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

 fully I mm. wide. 7. .S". speciosa. 



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

 narrowed apex. 8. S. tdis;inosa. 



Achenes pubescent. 9. S. Purshii. 



Bracts of the involucre acute or acutish. 10. S. puberula. 



Panicle or thj-rsr.s 1 -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. S. paiula. 

 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'. ulmifoHa. 



Involucre campanulate, many-flowered. 



16. 5. arguta. 

 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". serotina. 



Stem pubescent. 



a. Cauline leaves with relatively long blades, acuminate. 

 Blades of the cauline leaves of a linear type. 



20. S. 711 pes Iris. 



