264 A NATURALIST IN THE GREAT LAKES REGION 



FIG. 394. Sarsaparilla, 

 A r alia nudicaulis. 



It is evident that the edges of the ravine slope must be dry 

 areas, for the soil moisture will readily drain out into the ravine. 

 The deeper the ravine, the farther back from its edge the dry 

 area will run. As you approach the rock 

 ravine through the forest in the Starved 

 Rock region there is a marked change 

 in the vegetation, the mesophytic forms 

 giving way to xerophytic sorts. Black 

 oaks replace the red and white. Such 

 shrubs as panicled dogwood, sumac, 

 chokecherry, and ninebark^ are charac- 

 teristic. Patches of hairycap moss and 

 horsetails, indicative of xerophytic con- 

 ditions, appear along the edges of the 

 ravine openings. Junipers are growing 

 and such deciduous shrubs as the blue- 

 berry and huckleberry. These and such flowering plants as the 

 false lily-of-the-valley and bastard toadflax found growing here 

 are characteristic of the pine region in 

 the Dunes. 



The sides of the ravines support an 

 abundant vegetation if they are sloping 

 and have some soil. Cinnamon and 

 interrupted ferns may grow on the banks. 

 Where the sides are steeper still and 

 rocky, red cedar, balsam, ninebark, 

 gooseberry, and other plants gain pre- 

 carious footings (Fig. 393); columbine, 

 bluebells, Prenanthes, sarsaparilla (Fig. 

 394), shooting star occasionally, and such 

 ferns as the fragile fern (Fig. 395) and 



FIG. 395. Fragile fern, 

 Cystopteris fragilis. 



bladder ferns (Fig. 396) are to be found growing in the cracks 

 and crevices. In all of the ravines it is noticeable that vegeta- 

 tion is much more abundant on the shady side than on the side 

 exposed to the sun. Farther down in the bottom of the ravine 



