2o8 . The Ohio Naturalist. [Vol. XI, No. 1, 



The forest formation extends across the island from margin to 

 margin and presents two distinct zones : 1 . A border zone 20-50 

 feet wide, consisting in part of large trees, the remnant of the 

 original forest. It is a very open border, not more than three 

 trees deep, the tallest of these trees having attained a height of 

 60-65 feet. The shrub stratum is very poorly developed. It is rep- 

 resented on the south side by a few Cornus, Rosa and Cephalanthus, 

 at the outer margin of the zone ; these are wanting on the north side. 

 The field stratum is composed almost wholly of grasses of which 

 Muhlenbergia diffusa, Agrostis perennans and Syntherisma san- 

 guinalis and linearis are the principal species. Associated 

 with these is a scanty growth of herbs; and on the south side an 

 abundant growth of Rhus toxicodendron, Parthenocissus quinque- 

 folia and Vitis vulpina, trailing over the ground. The Rhus has 

 also climbed two Ulmus americana. The grass and weeds have 

 been mowed, so that the shrubs too are kept in a stunted condition. 



Surrounded by the older forest zone lies a rejuvenated area 

 clothed with young forest trees, among which Ulmus Americana 

 predominates, fully nine-tenths of the trees are of this species. 

 This is a part of the area which was cleared sixteen years ago ; but 

 the forest has again invaded the area and become established. 

 The ground slopes gently toward the southeast and more abruptly 

 toward the northwest. The elevation of the highest portion is not 

 more than 4 or 5 feet above the standard water level. The gentle 

 slope and the thin shade of the young trees, together with the 

 loose light soil, provide a dry sunny habitat on which Carduus, 

 Aster, Arctium, Hedeoma, Nepeta, Erigeron and other sun loving 

 plants find a congenial environment. There were the remains of 

 large Burdocks and large Rubus nigrobaccus canes. There are 

 scarcely any grasses in this central area ; and as it has been mowed 

 and burned all the herbage is scanty. 



On the northwest margin of the transect the forest formation 

 is followed immediately by the marsh-herb formation. The 

 marsh-shrub formation is wanting. The marsh-herb formation is 

 represented by four societies : 



8. Hibiscus moscheutos society, 



9. Polygonum-Scirpus society, 



10. Scirpus lacustris society, and 



11. Nelumbo-Potamogeton society, none of which shows the 

 development of the marsh zones on the south side. 



8. Hibiscus moscheutos society. 

 Facies. 

 Hibiscus moscheutos. 



Secondary species. 



Hypericum mutilum. Bidens cernua. 



Impatiens fulva. Xanthium canadense. 



Hedeoma puligioides. Rosa Carolina. 

 Panicum walteri. 



