170 Rhodora [SEPTEMBER 
but not the third, there is to be found in the characteristics of these 
areas some influence or group of influences which is of fundamental 
importance in the distribution of plants. 
If we seek in the precipitation and exposure of such districts as the 
tableland of Table-top Mt. (Group I), the northwestern escarpments 
of Table-top (Group II), and the tableland of Mt. Albert (Group II), 
an explanation of the very dissimilar floras of these areas we shall find 
that, as we should expect, these closely adjacent slopes and summits 
(the northwestern escarpments and the western edge of Table-top 
only about ten miles east of the tableland of Albert) have no apparent 
difference in the amount of precipitation. Nor is the exposure of 
these cloud-enshrouded districts a significant factor. The flat table- 
land of Mt. Albert, for instance, and its cafion-valleys with walls facing 
north, south, east, and west support an essentially uniform flora; 
similarly, upon Table-top a uniform flora is found upon north, south, 
east, and west exposures as well as upon the level portions of the 
tableland. Precipitation and exposure are, then, of only minor 
importance in determining the localized distribution of our alpine 
plants. 
In attempting to account for the peculiarities of plant distribution 
much stress has been laid of late upon the degree of fineness or coarse- 
ness of soils, and their water-content. But to those intimate with the 
occurrence of our alpine plants these factors, again, seem of secondary 
importance. For instance, Cystopteris montana on Mt. Albert grows 
in equal abundance on the firm and steep amphibolite cliffs and in 
the deep, fine and saturated alluvium of mountain streams. Sela- 
ginella selaginoides, abundant in the wet mossy bogs of Bonaventure 
and Gaspé Counties, Quebec, is quite as much at home in the well- 
drained alpine meadows or in the crevices of either wet or dry rocks, 
in the latter situation merely becoming stiffer and more stocky than 
in deep shade or moisture. Zygadenus chloranthus is apparently 
indifferent whether it is in the crevices of sun-baked rock, on cold cliffs, 
in river-alluvium or in wet bogs. Similarly, many other members 
of the flora characteristic of the areas classed as Group II grow in 
wet or dry, fine or coarse soils. 
The distinctive plants of Groups I and III, likewise, show a remark- 
able indifference to the coarseness or fineness, the dryness or satura- 
tion of their supporting soils. Empetrum nigrum, Ledum gqroenlandi- 
cum, Vaccinium Vitis-Idaea, var. minus, and Prenanthes trifoliolata, 
