148 J. E. CRIBBS 



spring rains before the appearance of the vernal flora; and, 

 excepting the .mechanical effect of the impact of floating ice 

 upon the trees near the channel, seldom has much direct effect 

 upon the vegetation. The period of submergence is usually too 

 brief, and the amount of sediment deposited at the time of the 

 recession of the waters to the original channel is generally in- 

 sufficient, to injure the development of vernal species. 



In composition the forest of the floodplain is typically meso- 

 phytic. Among its members are a few species which are es- 

 pecially characteristic of this situation, and a large number 

 which are typical of the mesophytic forest in general. Of those 

 especially referable to this habitat may be mentioned Ulmus 

 americana, Platanus occidentalis, Acer saccharinum, Juglans 

 cinerea, Quercus bicolor, Iris versicolor, Acer saccharum, Carya 

 ovata, Carya laciniosa, Salix nigra, Mertensia virginiana, Echi- 

 nocystis lobata, Polygonatwn commiitatum, Acorus calamus, 

 Lobelia siphilitica, etc. Of these Carya, and Acer saccharum, 

 are generally dominant species and not uncommonly form almost 

 pure stands. 



The remaining members of the forest are largely representatives 

 of the mesophytic deciduous forest of the uplands also; and, as 

 an account of the composition there will be given under the 

 discussion of that subject, it will suffice here to note some of the 

 general features only. 



Perhaps one of the most noticeable features of the floodplain 

 forest s the unusual assemblage of vernal species. The rich 

 humus and alluvial soil afford an excellent environment for the 

 development of this type. One encounters the following species 

 here, and frequently in great abundance: Phlox divaricata, 

 Viola cucullata, Viola pubescens, Viola pallens, Erythronium 

 americanum, Geranium maculatum. Podophyllum peltatum, Clay- 

 tonia virginiana, Anemone quinquefolia. Anemone pennsylvanica, 

 Trillium grandifiorum, Trillium erectum, Streptopus amplexi- 

 folius, Thalictrum dioicum, Smilacina racemosa, Hepatica aculi- 

 loba, Mertensia virginiana, Senecio aureus, Dicentra Cucullaria, 

 Cypripedium parviflorum, Botrychium virginianum, Panax tri- 

 folium. Iris versicolor, Anemone thalactr aides, etc. 



