THE DUNES OF LAKE MICHIGAN 207 



is really so. All the annual species that grow on the middle 

 beach, as for instance Cakile maritima, Salsola kali, A triplex 

 Uttoralis and Atriplex laciniata, are more or less succulent and 

 belong to the halophytic type of growth. The same holds good 

 for the species of the upper beach: here we find the same forms 

 that occur on the middle beach and besides these many other 

 halophytes, such as the succulent Honkenya peploides and Con- 

 volvulus soldanella and the glaucous wax-coated A gropyrum jun- 

 ceum — all three in possession of subterranean runners — and the 

 also succulent Euphorbia Paralias, a form that assimilates even 

 in winter — as do many plants in our dunes — and multiplies by 

 adventitious shoots from the roots. In short, we may say that 

 the vegetation of our shore is distinctly halophytic. Even in 

 our coastal dunes species with distinct halophytic characters 

 are found, e.g., the wax-covered Eryngium maritimum and Glau- 

 cium lutum, forms that dislike to grow away from the sea and 

 seem to need, if not salt in the soil, then at least salt in the air. 

 If we now compare with these conditions the situation on the 

 shore of Lake Michigan, it must strike us at once, that there the 

 aspect of the beach-flora is not halophytic. Such characteristic 

 beach-plants as Euphorbia polygonifolia, Artemisia caudata and 

 A. canadensis, Cirsium Pitcheri, Xanthium canadense, which we 

 collected near Miller and Dune Park, Indiana, or Strophostyles 

 helvola and Petalostemum purpureum, which we saw at Lake 

 Bluff, Illinois, can not be said to have a halophytic appearance, 

 nor can Potentilla Anserina, which Fuller mentions as charac- 

 teristic of the beach in the list of dune-plants in his The vegeta- 

 tion of the Chicago Region, but which I cannot remember, to 

 have found. So we have learned to know a first interesting point 

 of difference between the dunes of Lake Michigan and those in 

 Holland. This point becomes still more interesting, when we 

 hear that after all some true halophytic species are to be found 

 on the shore of the fresh water Lake of Michigan. The some- 

 what fleshy annual Euphorbia polygonifolia is properly speaking 

 an example of this kind. I have found this same species near 

 Wood's Hole, Massachusetts, on the beach of the Atlantic. 

 Some other instances can easily be given. On the eastern shore 



