152 Bulletin Wisconsin Natural History Society. [Vol. 8, No. 3. 



south. At Chicago, and along the east shore, Dr. Cowles found 

 the following species to be most characteristic almost everywhere : 

 Artemisia caudata. Artemisia canadensis, Cirsium pitcheri, Eu- 

 phorbia polygonifolia, Lathyrus maritimus, Oenothera biennis, 

 and Agropyrum dasystachyum, the two last-named especially 

 northward. 



( )n the other hand, the writer found, in the summer of 1902, 

 on a more Northern beach, to-wit at Mackinaw City, the following: 

 Potentilla anserina, Oenothera biennis. Salix adenophylla, Comus 

 stolonifera, Rosa Sayii, Anemone multifida ; and not far away, on 

 Bois Blanc Island, where the beach was rather shingly and con- 

 tained some small lagunes : Carex hystericina, Cares aurca, Gen- 

 tiana sp., Lobelia Kalmii, Gerardia paupercula, Prenanthes race- 

 mosa, Impatiens fulva,Larix Americana, Thuya occidentalis; while 

 a neighboring sand beach showed : - Irfemisia canadensis, Elymus 

 canadensis, Lathyrus maritimus, Rosa Sayii, Prunus pumila, Rhus 

 toxicodendron, Arctostaphylos uvaursi. Certainly very different 

 types of vegetation on apparently similar stations. But it should 

 be remembered that these Northern beaches are on low shores 

 instead of at the foot of clay banks. 



From the above it appears that the beach flora of Milwaukee 

 is unusually scanty. Leaving out of account the stragglers from 

 the bank (and also some undetermined algae which are common in 

 spring at the upper edge of the lower beach ), there are really only 

 four characteristic beach species: Cakile, Euphorbia, Lathyrus 

 and Potentilla, and even of these Euphorbia and Lathyrus are not 

 confined altogether to the beach. 



E. The ('11 forested Hanks. 



Far more complicated than the flora of the beach is that of the 

 banks. There are portions of the latter totally devoid of vegeta- 

 tion ; these are the vertical and rapidly receding cliffs of the head- 

 lands and other portions where erosion is unusually active. There 

 are other portions partially clothed with herbaceous and shrubby 

 species ; and still others bearing fairly prosperous forests. 



Evidently a cycle of development starts with complete bareness. 

 Plant invasion begins either from the upper edge, or more fre- 

 quently from below. Very often also the inner sides of erosion 

 terraces, or the immediate surroundings of the numerous little 



