158 
Ohio Biological Survey 
stream is rapid, and its valley sides much steeper than is the case with 
longer streams. Along such streams are found many of our steepest 
slopes. The valleys are so narrow everywhere that the contrast between 
the parts in the Maysville limestone and in the Eden shale is not often 
well marked. 
Northward flowing streams. —North flowing and south flowing 
streams of this sort show much the same differences that were noted be¬ 
tween north and south slopes. Along the northward flowing streams, are 
the most mesophytic forests of the region. The tree growth is more 
varied than elsewhere, and almost every mesophytic species of the region 
may occur. In such a forest, beech forms about fifty per cent of the 
tree growth. The remaining fifty per cent is made up chiefly of sugar 
maple (Acer sacchariim), tulip tree (Liriodendron Tulipifera), wild black 
cherry (Primus serotina), rock elm (Ulmus racemosa), big shell-bark 
hickory (Carya laciniosa), mulberry (Morns rubra), and basswood (Tilia 
americana). On some slopes beech predominates, but rarely forms over 
eighty per cent of the forest. The line transect, fig. 28 , shows the compo¬ 
sition of a representative mesophytic forest of this type. 
The undergrowth is dense, consisting of saplings of the trees named 
above, with a large amount of dogwood (Cornus florida), ironwood (Car- 
pinus caroliniana), papaw (Asimina triloba), and spice bush (Benzoin 
aestivalc), and sometimes moosewood (Dirca palustris) and elder (Sambu- 
cus canadensis). Lianas are represented by wild grape (Vitis aestivalis), 
Virginia creeper (Psedera quinquefolia) and green brier (Sniilax his- 
pida). Because of the very dense shade of this forest, summer herba¬ 
ceous vegetation is scarce. It consists only of a few thin-leaved shade 
plants, as Pilea pumila, Impatiens pallida and I. biflora, Actaea alba, Des- 
modiuni pauciflorum and D. gran dido rum, Aralia racemosa, and a number 
of ferns, often in large patches (fig. 2 q). The vernal vegetation is ex¬ 
tremely luxuriant. The ground is carpeted with dense mats of squirrel 
corn and Dutchman’s breeches (Dicentra canadensis and D. Cucullaria), 
dog’s tooth violet (Erythronium americanum and E. albidum), twinleaf 
(Jeffersonia diphylla), and many other species less abundant. 
This mesophytic forest prevails on all slopes up to about 25 degrees. 
Steeper slopes have some oaks upon them (Quercus Muhlenbergii, Q. 
alba, and Q. rubra), and the herbaceous growth is less mesophytic. Here 
are usually found buttercup (Ranunculus hispidus), Greek valerian 
monium re plans), rue anemone (Anemonella thalictroides), meadow rue 
