248 A NATURALIST IN THE GREAT LAKES REGION 



fluviatilb is prevalent. 

 Other forms are smart- 

 weeds, Polygonum lapath- 

 ifolium (Fig. 360) and 

 P. persicaria, chickweed 

 (Fig. 361), bitter cress (Fig. 

 362), Viola blanda, mermaid 

 weed (Fig. 363), skull cap 

 (Fig. 364), cardinal flower 

 (Fig. 365). 



The grass an4-sedge 

 formation described above 

 may give place-to the 

 prairie, at first to :the wet 

 prairie and finally to the 

 typical upland prairie. Both 

 of these areas manifest 

 marked seasonal changes as 

 indeed do most areas. One 

 set of plants comes on to 

 maturity, blossoms, fruits, 

 and gives way to a later set, 

 which in turn becomes in- 

 conspicuous as some other 

 assumes for the time being 

 the conspicuous role. Thus 

 Viola blanda and V. peda- 

 tifida blossom early on 

 the prairie, shooting star 

 (Fig. 366) comes then, wild 

 hyacinth (Fig. 367) by June, 

 then wild onions (Fig. 368), 

 Culver's root (Fig. 369) and 



,. ,. golden old man (Fig. 370) 

 FIG. 365. Cardinal flower, Lobelia cardi- 6 



fa. follow. Brown-eyed Susans 



