Vegetation of Northern Cape Breton. 313 



run north-and-south, and where both flanks are thus equally well 

 exposed to the sun, on the other hand, the ravine forest may be 

 wholly of the deciduous type. 



One feature of coniferous ravine forests worthy of special 

 mention is their great mesophytism, as evinced more particularly 

 by the wonderful development of the bryophytic ground cover. 

 Commonly the ground beneath the trees is literally buried beneath 

 a thick bed of liverworts and mosses. The sphagnums in 

 particular — such species as Sphagnum capillaceum tcnellitm, S. 

 Girgensohnii, S. quinquefarium, and 5". subsecundum — commonly 

 form wide, deep cushions, flourishing here as in no other upland 

 habitat in this region. 



The summer evaporating power of the air in coniferous ravine 

 forests, as compared with other habitats. — During the summer 

 of 191 5 a series of porous cup atmometers was operated, for a 

 period of a little more than two weeks, in various habitats, with 

 the object, primarily, of ascertaining the relative evaporating 

 power of the air in coniferous ravine forests as compared with the 

 deciduous climax forests. The habitats selected were as 

 follows : 



Station i ("Open — Shore") : Open hillside, east exposure, 

 half a mile from seacoast. 



Station 2 ("Open — Intervale") : Open hillside, east exposure, 

 four miles from coast at head of intervale. 



Stations j and 4 ("Hardwood") : Hardwood (climax) virgin 

 forest ; east exposure ; near station 2. 



Station 5 ("Ravine Conifer — High"): Coniferous forest; 

 steep north-facing slope of ravine, about 250 feet above river ; 

 near station i. 



Station 6 ("Ravine Conifer — Low") : Dense coniferous forest; 

 steep north-facing slope of ravine, about 150 feet above river; 

 near station 7. 



Station 7 ("Ravine — Bed"): Gravel bar in bed of stream; 

 exposed to sun about six hours daily ; stream bed about 75 feet 

 wide at this point ; near station i. 



The readings obtained are given in Table VI. During 'much 

 of the period that the cups were in operation the weather was 

 intermittently rainy, foggy, and clear. From August 3 to 

 August 7, however, it was uninterruptedly clear, so that for pur- 



