Vegetation of Northern Cape Breton. i 371 



vegetation differs quite perceptibly from that of the drier diffs 

 described earlier under the xerarch series. It is of course diffi- 

 cult to draw sharp lines, since there are all degrees of intergrada- 

 tion. Here, as there, the most distinctive plants are the 

 bryophytes, which thrive in crevices and frequently plaster over 

 even precipitous rock surfaces. But in addition to various 

 of the species cited earlier as characteristic of relatively dry 

 cliffs, there occur here, usually as the predominant forms, various 

 more or less hydrophytic species. Prominent among these are 

 the sphagnums, the species mainly those mentioned elsewhere in 

 connection with the ravine forest, and the liverworts and mosses 

 enumerated in the subjoined list. 



Marsupella emarginata Didymodon riibellus 



Sphenolohus Michauxii Hymenostylium curvirostre 



Mylia Taylori Anoectangium Mougeotii 



Plagiochila asplcnioides Plagiothechim dentiadatum 



Diplophyllum albicans Hylocomium hrevirostre 



Scapania nemorosa Plagiopiis Ocderi 

 Blindia acuta 



C. THE ASSOCIATION-COMPLEXES OF FLOOD PLAINS 



Here should be included the strips of swale which not infre- 

 quently border even rapid streams and which obviously represent 

 incipient flood plains. In valleys, for example, and locally even 

 in ravines, a narrow, marshy strip frequently intervenes between 

 ordinary summer water level and the lower edge of the upland 

 forest. The vegetation in such a tract is essentially that of a 

 well-drained swamp, with sedges, such species as Carex torta 

 and C. aquatilis, and the grass, Calamagrostis canadensis, 

 usually the predominant forms. Swampy flood plains of this 

 particular sort are much more extensively developed on the- 

 plateau (see p. 456) than in the lowland, where they are of 

 minor consequence. 



Of much more importance here, though somewhat restricted 

 in their occurrence, are the flood plain formations which have 

 been developed in particular at the mouths of some of the larger 

 streams, as at the heads of Ingonish Harbor, Middle Harbor 

 (Aspy Bay), and Margaree Harbor. The earlier phases of the 

 hydrarch series of association-types, which reaches its culmina- 



