36 UNIVERSITY OF MISSOURI STUDIES [178 



Streams and the borders of alluvial woods. These are the char- 

 acteristic species : 



Asplenium pycnocarpon I. biflora 



Impatiens aurea Cacalia reniformis 



f. AUuviales urticoides. The nettle association ot 

 alluvial herbs, composed of shade-loving, often stinging plants, 

 may be considered the herbaceous flora proper to the alluvial 

 forest. With the nettles occur a few other herbs, mainly of 

 weedy types, only a few, such as Campanula Americana and 

 Eupatorium ageratoides, are of any beauty : 



Urtica gracilis Circaea Lutetiana 



Laportea Canadensis Scrophularia Marylandica 



Pilea pumila Phryma Leptostachya 



Boehmeria cylindrica Campanula Americana 



Parietaria Pennsylvanica Eupatorium ageratoides 



Polygonum Virginianum Solidago flexicaulis 



P. scandens Polymnia Canadensis 



Chenopodium hybridum (local) 



Geum Canadense Ambrosia trifida 



Amphicarpa monoica Actinomeris squarrosa 



Hypericum corymbosum Mulgedium leucophaeum 



H. mutilum 



In places the alluvial forests have a noticeable sward in 

 autumn, composed chiefly of Leersia Virginica and Mnhlenher- 

 gia Mexicatia and M. racemosa. Other grasses, notably Cinna 

 arundinacea, Diarrhena Americana, and Uniola latifolia, are oc- 

 casional. 

 B. Sylvales. Plants of the mesophytic forest zone. 



The sylvan flora finds its best development in the virgin for- 

 est of the midlands. Such tracts, however, are hard to find. If 

 by virgin is meant the forest as it was before the advent of civil- 



