208 THEO. J. STOMPS 



of Lake Michigan the chief character-species of the middle 

 beach, but thriving also on the upper beach or on windward 

 slopes of active dunes, is the annual succulent Cakile edentula. 

 This species also, a perfect imitation of our European Cakile 

 maritima, I have collected near Wood's Hole, Massachusetts, 

 and towards the end of our journey we have met with it again 

 on the Pacific Shore at Carmel, California. Another halophyte, 

 that we saw on the beach and in the dunes near Miller and 

 Dune Park, Indiana, is the succulent annual Corispermum hys- 

 sopifolium, in Europe often locally a characteristic plant of the 

 dune-flora of the coast. In Holland too it has been found, 

 though in our country Corispermum Marshallii is more common, 

 typical of abandoned potato fields in the dunes in the neighbor- 

 hood of the sea. On the upper beach at Lake Bluff, Illinois, we 

 studied among others a very interesting association of Lathyrus 

 maritimus. This too is a marine species, occurring frequently on 

 the Atlantic shore of America. It belongs also to the European 

 coast-flora, having been found, e.g., on the Dutch beach. Finally 

 I could mention the Russian thistle, the variety tenuifolia of 

 Salsola Kali, which I remember from our visit to Miller, Indiana. 

 This example however is less important, because we are treating 

 the feature of the beach-flora, but we did not find this species 

 on the beach, but only in the dunes proper. Coming to a con- 

 clusion we may say, that, though the beach-flora of Lake Michi- 

 gan on the whole is not so halophytic as it is in Holland, still 

 some true halophytic types are present. It is not difficult to 

 explain this fact, which at first sight might cause surprise. Life- 

 conditions on the shore of Lake Michigan are extremely xero- 

 phytic, the summer sun being very hot and a strong wind loaded 

 with sand blowing generally along the plants. We know that 

 halophytes are merely a form of xerophytes, as much salt in the 

 soil renders it physiologically very dry. It is therefore clear that 

 the life-conditions on the non-saline shore of Lake Michigan are 

 xerophytic to such a degree that they become almost equivalent 

 to the halophytic conditions that exist, e.g., in the neighborhood 

 of Wood's Hole, Massachusetts, enabling in this way such plants 

 as Euphorbia polygonifolia, Cakile edentula, Corispermum hys- 



