24 Flora of Denver. 



191. Xanthium Canadense MILL. (CocKLE-BuR. > Common 

 along the streams, fall. 



192. Rudbeckia hirta L. (CONE-FLOWER.) Erect, rough 

 hairy, rays yellow; disk brownish-purple, thimble-shaped. 

 Along the Platte. Summer. 



193. Lepachys columnaris TORR. & GRAY. (COLUMN- 

 FLOWER.) Stems rather tall, usually several from the root,, 

 heads often solitary, yellow rays reflexed, disk columnar, dark 

 brown. Along the ditches and on the plains. Common. The 

 var. pidcherrima Torr. & Gray is also found. It has the rays 

 wholly or in part brownish purple. Along the Platte, less 

 common. Summer. 



194. Lepachys Tagetes GRAY. Leaves with stiff lobes, 

 white bristly, smaller than the preceding. Heads much smaller, 

 rays very dark brown. Rare in North Denver, near Rocky 

 Mountain Lake. Fall. 



195. Gymnolomia multiflora BENTH. & HOOK. Simple 

 stemmed or much branched, usually with numerous heads of 

 yellow flowers an inch in diameter. Smaller and more slender 

 than the sun-flower. Along the Platte, summer and fall. 



196. Helianthus a'nnuus L. (SUN-FLOWER.) The common 

 large flowered and large broad-leaved sun-flower. Summer to 

 fall. 



197. Helianthus pumilus NUTT. Chiefly branched from 

 the base, very stiff, with thick stiff rough leaves, disk yellow. 

 Berkeley Hills. Summer and fall. 



198. Helianthus petiolaris NUTT. A foot or more high, 

 branching, heads usually solitary on the branchlets, disk dark 

 brown, heads 1J-2 inches in diameter. The common sun- 

 flower of the plains. Summer to fall. 



