164 THE CANADIAN NATURALIST. [May 



plants requiring much alkali, many other localities must be well 

 suited for species to whose growth lime is more necessary. And 

 again, the different proportions in which lime exists in soils over- 

 lying the Silurian and Devonian rocks, make it probable that in 

 many localities the proportion would be so small as to afford suita- 

 ble habitats for plants preferring non-calcareous soils. However 

 much, then, there may be in the relation existing between plants 

 and the chemical constituents of the soils in which they grow, it 

 seems exceedingly difficult to arrive at any satisfactory conclusions 

 regarding the effect of this relation upon the general distribution 

 of our native plants. 



In the above remarks I do not of course include any reference 

 to sea-shore plants, which, without a doubt, derive sustenance from 

 the chloride of sodium, with which both the air and soil, in 

 the vicinity of the coast, are to some extent impregnated. But 

 the very fact that many of these plants ar$ met with in localities 

 far distant from any possible influence of the ocean, clearly shows 

 that this alkali may not be entirely essential to the existence of 

 all maritime species. \ 



Before leaving the subject, a few instances of apparent prefer- 

 ences for particular soils or locations may be cited. The white- 

 wood, Platanus occidentalis Linn., is, at London, only met with on 

 the low alluvial flats on either side of the Biver Thames, and the 

 two or three trees occurring at Toronto exist in a similar situation 

 on the banks of the Biver Don. At Chatham, and nearer the 

 mouth of the Biver Thames, this one of the largest of Canadian 

 trees occupies like locations, and is said to attain there a mag- 

 nificent size. Pinus rigid" Miller, again, has only been detected 

 the Thousand Islands — which form the connecting link 



a 1110112: 



s 



between the Laurenticle hills of Canada and the Adirondacks of 

 New York State — and in the Township of Torbolton on the L T pper 

 Ottawa, in the immediate vicinity of which the Laurentian strata 

 are also largely developed. Corydalis glauca Pursh, K<tlmi<( 

 anqustifolicL Linn., Asplenium ebeneum Aiton, and Woodsia 

 liven six B. Brown — for the most part easily recognized plants — 

 are, induing by our present knowledge of their distribution in 

 Canada, limited in range to the area occupied by the Laurentian 

 rocks. The distribution of these and other species is not, how- 

 ever, so definitely established as to warrant any perfectly safe con- 

 clusions regarding the effects upon them of particular soils and 

 ocations. and other reasons already mentioned would further 



