78 
Cheney and True—Flora of Madison and Vicinity . 
Polymnia, L. Leaf-cup. 
287. P. Canadensis , L. 
Growing in low wet woods about Lakes Wingra 
and Monona. Not common. 
Silphium, L. Rosin-weed. 
288. *S. laciniatum , L. Rosin-weed. Compass-plant. 
Growing along railroads and on little spots of wild 
land in fields. Not rare. 
289. *S. terebinthinaceum , L. Prairie dock. 
With S. laciniatum. 
290. S. integrifolium , Michx. 
Throughout the region in dry open places. Com¬ 
mon. 
291. S. perfoliatum , L. Cup-plant. 
Growing in moist places. Not common. 
Ambrosia, Tourn. Ragweed. 
292. *A. trifida , L. Great ragweed. 
Low places, especially banks of streams. Common. 
293. *A. artemisicefolia , L. Roman wormwood. Hog-weed. 
Bitter-weed. 
This is perhaps our commonest weed, growing in 
all soils under all sorts of conditions. 
Xanthium, Tourn. Cocklebur. Clotbur. 
294. X. Canadense , Mill. (X. strumarium, L.) 
Cultivated lands everywhere. In many places a 
very troublesome weed. Not especially abundant 
in this region. 
Heliopsis, Pers. 
295. //. Icevis , Pers. 
Rather common everywhere. 
Rudbeckia, L. Cone-flower. 
296. R. ladniata , L. 
Low thickets and borders of woods. Not common. 
. 297. R . hirta , L. 
Growing on dry soil everywhere. 
