I2Q 



182a. Leaves all or chiefly at the base (5 10 dm. high) 



Sunflower, Helianthns occidentals. 



182b. Leaves chiefly scattered on the stem 183. 



183a. Leaves mainly or all alternate, and not definitely 3-ribbed 



(14 m. high) 184. 

 183b. Leaves mainly or all opposite, lanceolate to ovate, and 3-ribbed 



186. 



184a. Stem glabrous Sunflower, Helianthus grosse-serratus. 



184b. Stem hairy or rough 185. 



185a. Leaves hairy beneath, rough above, lanceolate 



Sunflower, Helianthus giganteus. 

 185b. Leaves rough on both sides, elongated 



Sunflower, Helianthus maximiliani. 



186a. Leaves sessile (5 15 dm. high) 187. 

 186b. Leaves petioled, or narrowed at the base into a petiole 

 (530 dm. high) 189. 



187a. Leaves wedge-shape at the base 



Sunflower, Helianthus doronicoides. 



187b. Leaves rounded at the base 188. 



188a. Stem glabrous or nearly so 



Sunflower, Helianthus diyaricatus. 



188b. Stem densely and softly hirsute 



Sunflower, Helianthus mollis, 



189a. Stems rough, pubescent, or hispid 190. 

 189b. Stems glabrous or nearly so 193. 



190a. Leaves narrowly lanceolate, more than 5* times as long 

 as wide Sunflower, Helianthus giganteus yar. subtuberosus. 



190b. Leaves ovate-lanceolate, not more than 4 times as long 

 as wide 191. 



191a. Leaves rounded at base, above the petiole 



Sunflower, Helianthus hirsutus. 



191b. Leaves narrowed to the base 192. 



192a. Bracts of the involucre spreading 



Jerusalem Artichoke, Helianthus tuberosus. 

 192b. Bracts all appressed Sunflower, Helianthus laetiflorus. 



193a. Heads 3 cm. wide or less, including the rays 



Sunflower, Helianthus micro cephalus. 



193b. Heads 4 cm. wide or more, including the rays 194. 



194a. Leaves narrowed at the base into a winged petiole 195. 

 194b. Petiole slender, not winged 



Sunflower, Helianthus decapetalus. 



