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George E. Nichols, 



slopes which face directly on the shore and therefore are most 

 exposed to the action of waves and spray (Fig. 3). Along such 

 bluffs there is usually a pronounced zonational arrangement of 

 plant associations. Between low and high tide levels, wherever 

 the base of the bluffs is submerged, the rocks are usually plastered 

 with sea-weeds, prominent among which are species of Fuciis 

 and Ascophylliim. Above high tide level is a zone of varying 

 width in which, owing largely to the mechanical action of waves 



Figure 22. — Juniperus horisontalis on sea bluff; Middle Head, Ingonish. 



and ice, vegetation is absent. Higher up, and sometimes reach- 

 ing to a height of thirty-five or forty feet, is a zone in which 

 the vegetation consists largely of scattered halophytic crevice 

 plants. The upper limits of this zone are presumably determined 

 by the height of the waves in winter storms. The most abundant 

 plant here is Plantago decipiens, along with which commonly 

 grow Solidago sempervirens and Sagina procumbens — the latter, 

 of course, hardly to be considered a typical halophyte. Other 

 halophytic species which may inhabit crevices or ledges toward 

 the upper edge of this zone and which, like the preceding, may 

 also occur on low headlands far beyond the actual reach of the 

 waves, are Potentilla pacifica, Atriplex patula hastata, and 

 Lathyrus maritimus. The most characteristic plant on that part 



