3M 



George E. Nichols, 



TABLE VI 



Rate of Evaporation in Various Habitats, as Indicated by the Porous 



Cup Atmometer 



July 22- 



July 27 



28. 8 CC. 



39.4 CC. 

 16.0 CC. 



Station I: Open — shore 



Station 2: Open — intervale 



Station 3: Hardwood A 



Station 4: Hardwood B 15.3 cc. 



Stations: Ravine Conifer — high. . . . j 14.4 cc. 



Station 6: Ravine Conifer — low....! ii.o cc. 



Station 7: Ravine — bed 24.1 cc. 



July 27- 

 August 3 



45.0 CC. 

 53-3 cc. 

 19.6 cc. 

 16.3 cc. 

 20.6 cc. 



14.0 cc. 



31. 1 cc. 



August 3- 

 August 7 



84.2 cc. 

 91.9 cc. 

 42.1 cc. 

 37.8 cc. 

 52.5 cc. 

 43-3 cc. 

 63.0 cc. 



Total 



158.0 cc. 



184.6 cc. 



77.7 cc. 



69.4 cc. 



87.5 cc. 

 68.3 cc. 



118. 2 cc. 



pose of comparison the third column of figures is the most 

 rehable. From an examination of these figures various facts 

 are obvious, but only one of these need be emphasized, namely, 

 that the evaporating power of the air in the coniferous ravine 

 forest dififers little from that in the climax deciduous forest. 

 Greater humidity, then, will not explain the luxuriant develop- 

 ment of the moss carpet in a ravine forest. Other explanations 

 have already been suggested. 



C. THE ASSOCIATION-COMPLEXES OF OPEN VALLEYS 



Chiefly by reason of the protection which they afford from 

 cold winds in spring and fall, open valleys (Fig. 20), in general, 

 present edaphic conditions which are more congenial to plants 

 of southward distribution than those of any other type of habitat- 

 complex. Robinson ('03) has already called attention to the 

 relative abundance in the intervales of eastern Nova Scotia of 

 early spring-flowering plants, and the writer (16^ pp. 252, 253) 

 has commented on parallel conditions in Connecticut. Nowhere 

 in northern Cape Breton are forests of the deciduous-hemlock 

 climax type more luxuriantly developed than on the floors of 

 broad, sunny valleys, i. e., in the interv^ales. Here, more 

 abundantly than anywhere else, grow the hemlock, red oak, white 

 ash. and elm (UlniJis americana) , among the trees, together with 

 various herbaceous plants of pronounced southward range. Of 

 the latter, many forms, such as Anemone virginiana, Sangtii- 

 naria canadensis, and Dicentra Cnctdlaria {fide Robinson '03), 

 Actaea alba, Epifagus virginiana, and Triostcnm aurantiacum. 



