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 cernuum 



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 terehin- 

 thinaceum, S.lacinia- 

 tum, and Eryngium jjf 

 yuccifolium are Al..^ 

 rare. W^m 



Naturally in any ^^^^, 

 region with as dis- 

 tinctive a group of 

 plants as exists in 

 the prairie there will 



. . Fig. 369 Fig. 370 



be a characteristic p^^g ^^^^ ^^^. p^^ 369 —culver's root, Veronica 



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



