Nov., 1910.] A Floristic Survey of Orchard Island. 
207 
The two bordering formations the marsh-herb on the one side 
and the forest on the other, merge in the areas between the shrub 
societies. The presence of seedling Ulmus, Ouercus and 
Gleditsia, in the Hibiscus-Typha society shows clearly that 
the forest is invading the marsh, and if the higher portion of the 
mud flat is not again submerged, the shrub zone may never 
become more complete than it is now; it may be formed farther 
down on the shore or it may be entirely replaced by the forest. 
The incompleteness of the shrub zone is due to the existence of 
the forest prior to the development of the marsh. 
III. Mesophy tic-forest formation. 
7. Ulmus-Fraxinus society. 
Facies. 
Ulmus americana. 
Fraxinus americana. 
Secondary species. 
Trees. 
Fraxinus nigra. 
Hicoria ovata. 
Hicoria minima. 
Ulmus fulva. 
Quercus palustris. 
Celtis occidentalis. 
Tilia americana. 
Gleditsia triacanthos. 
Morus rubra. 
Salix nigra. 
Lianas. 
Rhus toxicodendron. 
Vitis vulpina. 
Parthenocissus quinquefolia. 
Smilax hispida. 
Solanum dulcamara. 
Dioscorea villosa. 
Shrubs. 
Cornus stolonifera. 
Rubus nigrobaccus. 
Rubus occidentalis. 
Rosa Carolina. 
Cephalanthus occidentalis. 
Herbs. 
Muhlenbergia diffusa. 
Agrostis perennans. 
Syntherisma sanguinalis. 
Syntherisma linearis. 
Chaetochloa glauca. 
Carex tribuloides. 
Carex vulpinoidea. 
Carex frankii. 
Rynchospora alba. 
Solidago canadensis. 
Aster paniculatus. 
Aster sagittatum. 
Nepeta cataria. 
Teucrium canadense. 
Carduus lanceolatus. 
Arctium minus. 
Helianthus decapetalus. 
Urtica gracillima. 
Erigeron canadensis. 
Hedeoma puligioides. 
Mentha canadensis. 
Lycopus americanus. 
Oxalis stricta. 
Onagra biennis. 
Solanum nigrum. 
Epilobium strictum. 
Verbena urticifolia. 
Rumex obtusa. 
Geum canadense. 
Meibomia viridiflora. 
Eupatorium ageratoides. 
Eupatorium purpureum. 
Bidens bipinnata. 
Fungi. 
Agaricus campestris. 
Lycoperdon wrightii. 
