ECOLOGICAL STUDY OF BRUSH LAKE. 1 65 



Echinochloa crus-galli (L,. ) Beauv. Solatium nigrum L,. 



Panicum capillare L. Ambrosia artemisiaefolia L. 



Polygonum pennsylvanicum L. Leptilon canadense (L.) Britt. 



Phytolacca decandra L. Carduus lanceolatus h. 



The Phytolacca did not extend very far beyond the shrub 

 zone. In and outside of the shrub zone, which was composed 

 mainly of Cephalanthus, willows, dogwood and rose, there was 

 an abundance of sedges belonging mainly to the species — 



Carex lupulina Muhl. Carex muskingumensis Schw. 



" squarrosa L. 



As stated above, in and about this sedge society and extend- 

 ing down to the narrow shrub zone there is a remarkable zone of 

 young saplings and seedlings of Fraxinus americana L,. , forming 

 almost a continuous circle around the shallow bank of the filled 

 pond. These trees have probably developed within recent years 

 since the pond has practically become extinct. The forest zone 

 just outside of the sapling zone is rather dry and mesophytic and 

 consists of elms, ashes, cottonwoods, oaks, hickories, hackberries, 

 dogwoods, etc. 



In the spring of 1903 there was a partial reversion to former 

 conditions. A long period of abundant rains had filled the dry 

 basin, flooding even the shrub zone ; and the surface of the pond 

 was diversified by an abundance of the green leaves of Njmiphaea 

 ad vena Sol. One visiting this spot for the first time would never 

 have dreamed of the moist-ground weed society which had cov- 

 ered the place eight months before. With the return of the 

 water the pond lillies revived, although had the dry season con- 

 tinued for a year longer they would probably have mostly 

 perished. 



In this pond there will be an oscillation between hydrophyte 

 and mesophyte societies for many years to come. But finally the 

 last pond lily will disappear, having struggled not only against 

 living enemies, but against the inevitable change in the physio- 

 graphic conditions. The surface of the pond will then be rapidly 

 covered by a mesophytic forest, if man does not overrule the 

 orderly process of nature. At some distant day Brush Lake will 

 be in the same condition as the dying pond and only the spade or 

 drill will reveal the former existence of the present basin with its 

 hydrophytic flora. 



