242 Nichols: The vegetation of Connecticut 



The Mesophytism of the Flora in Rock Ravines. — A rock ravine, 

 more than any other sort of habitat, affords environmental condi- 

 tions congenial to pronounced mesophytic plants. Seepage water 

 is usually abundant along the sides, there is protection from sun 

 and wind, and the humidity of the air, as compared with the 

 surrounding upland, is high. Certain mosses and liverworts are 

 practically confined to such habitats. In a more arid region than 

 Connecticut the same observation might be made with regard 

 to many of the higher plants, but while it is a familiar fact that 

 in this region as elsewhere the flora of rock ravines includes many 

 of the most extreme shade- and moisture-loving ferns and flowering 

 plants, most of the species present are equally representative of 

 other habitats. Species intolerant of shade are largely excluded. 

 The majority of the forms cited in earlier papers as typical of 

 the climax forest of this region are to be found here, and not a few 

 of the common plants of rock ravines thrive elsewhere in wooded 

 swamps. The following list includes a number of ferns and 

 herbaceous flowering plants which may be considered character- 

 istic of rock ravines, though by no means peculiar to them. 

 Poly podium vulgar e Asarum canadense 



Phegopteris polypodioides Actaea rubra 

 Asplenium Trichomanes Caidophyllum thalictr aides 



Asplenium acrostichoides Chrysosplenium americanum 



Aspidium spinulosum Impatiens pallida 



Cystopteris bulbifera Viola cucullata 



Cystopteris fragilis Viola blanda 



Lycopodium luciduluni Viola rotundifolia 



Arisaema triphyllum Circaea alpina 



Smilacina racemosa Aralia racemosa 



Streptopus roseus Sanicula gregaria 



Trillium erectum Hydrocotyle americana 



Laportea canadensis Cryptotaenia canadensis 



Pilea pumila Collinsonia canadensis 



Solidago latifolia 



The Ravine Forest. — The intense mesophytism of a rock ravine 

 is further accentuated by the nature of the ravine forest (Fig. 3). 

 As a rule the hemlock and yellow birch are prominent, and more 

 often than not they predominate. Along with them commonly 



