916 Compositae Solidago 



E. Leaves triple-nerved, i. e., one pair of lateral veins decidedly more 

 prominent than the others. 

 Involucres 2-2.8 mm high. 



Stems glabrous throughout. (See excluded species no. 621, p. 1096) 



S. rupestris. 



Stems more or less densely pubescent. 



Stems glabrous below the inflorescence; leaves pubescent on the 



nerves beneath 10. S. canadensis. 



Stems densely pubescent throughout; leaves densely cinerous- 

 pubevulent beneath 10a. S. canadensis var. gilvocanescens. 



Involucres 3-8 mm high. 



Stems entirely glabrous, including the inflorescence. 



Plants flowering mostly from the last of August through Sep- 

 tember, of a prairie habitat; plants strongly stoloniferous, 

 the stolons forming sterile branches, usually with a terminal 

 rosette of leaves; leaves of stolons linear-lanceolate, mostly 

 7-15 mm wide, the veins conspicuous beneath, the margins 



usually strongly and evenly serrate above the middle 



11. S. glaberrima. 



Plants flowering mostly from the first of July to the latter part 

 of August; not strongly stoloniferous but with root stocks 

 at flowering time, these with elliptic, serrate leaves, the 

 blades sometimes 15 cm long on petioles of equal length.... 

 11a. S. juncea. 



Stems and inflorescence not entirely glabrous. 



Stems usually glabrous to the inflorescence or if pubescent not 

 rough. 

 Rootshoot leaves always present at flowering time; plants 

 flowering mostly from the first of July through August, 



usually of a dry habitat 11a. S. juncea. 



Rootshoot leaves absent at flowering time; plants flowering 

 mostly from the last of August through September, usually 

 of moist or wet places. 

 Leaves glabrous or somewhat scabrous above, pubescent at 



least on the midrib beneath 12. S. gigantea. 



Leaves glabrous above and beneath 



12a. S. gigantea var. leiophylla. 



Stems at least partly rough or scabrous. 



Stems minutely rough-pubescent above; leaves rigid, glabrous, 

 oblong-lanceolate, the lower ones mostly serrate toward the 

 apex. (See excluded species no. 622, p. 1096) . . . .S. Shortii. 

 Stems distinctly scabrous or pubescent their entire length. 



Cauline leaves of a lanceolate type 13. S. altissima. 



Cauline leaves of an oblong or oblanceolate type. 



Stems scabrous, green; rays 3-7. (See excluded species no. 



619, p. 1096) S. radula. 



Stems grayish pubescent or canescent; rays 5-9. 



Lower stem leaves 3-6.25 times as long as wide; in- 

 volucres 3-4.5 mm high 14. S. nemoralis. 



Lower stem leaves 7-10 times as long as wide; involucres 

 4.5-5.5 mm high. . . .14. S. nemoralis var. decemflora. 



