250 A NATURALIST IN THE GREAT LAKES REGION 



conspicuous, replacing in part the above-mentioned forms. 

 On thin-soiled prairie, or prairie with sandy soil, the pink and 



FIG. 368. Wild onion in blossom, Allium cermmm 



white prairie clover, Petalostemum (Fig. 377), and lead plant 



(Fig. 378) are apt to predominate, while such typical plants of 



the clay-soil prairie 



as Silphium lerebin- 



thinaceum, S.lacinia- 



tum, and Eryngium 



yuccifolium are 



rare. 



Naturally in any 

 region with as dis- 

 tinctive a group of 

 plants as exists in 

 the prairie there will 



be a characteristic 



FIG. 369 FIG. 370 



FIGS. 369, 370: Fig. 369. Culver's root, Veronica 

 assemblage of virginica; Fig. 370. Golden old man, Zizia aurea. 



