78 



appended map is drawn a line, north of which every weather 

 station record is said to show an average growing season of 153 

 days or less and south of which the average is 164 days or 

 more. It should be remarked, however, that in Connecticut 

 there are at least three stations south of this line which record 

 averages of less than 153 days, notably the station at Voluntown 

 where the records of twelve years seem to show an average grow- 

 ing season of less than 130 days. "This arbitrarily drawn line, 

 seems to separate, roughly speaking, the northern plants from 

 those more generally distributed." 



In the mind of the reviewer it seems extremely doubtful 

 whether, within the comparatively small area under surveil- 

 lance, it is possible to correlate the distribution of plants in gen- 

 eral with widespread climatic phenomena. It is of course not 

 disputed that cHmatic factors are of primary importance in 

 determining the geographic distribution of plants in the large. 

 And it may indeed be possible, even within the area in question, 

 to correlate with climate certain of the broader aspects of the 

 vegetation, as for example variations in the nature of the 

 cHmax forest on uplands.* But as affecting the distribution of 

 plants in general, it seems impracticable, except where pro- 

 nounced climatic dissimilarities, such as may be produced by 

 considerable elevations or proximity to seacoast, are observable, 

 to attempt to use variations in climate as a criterion. For even 

 within a tract of but a few square miles, due to differences in 

 slope, exposure, etc., there may exist a miniature diversity of 

 "climates" quite as appreciable as the more wide-spread dissimi- 

 larities upon which emphasis has been laid. Moreover, where 

 individual species of diverse habitats are concerned, physio- 

 graphic factors and soil conditions are of prime importance. 

 Within a very limited area like the one just assumed, there may 

 thus be encountered cliffs and sand-plains, bogs and swamps, 

 ravines and flood-plains — in other words, edaphic conditions 

 which would tend to exert an influence on plant distribution far 

 more profound than comparatively slight climatic differences. 



Coming now to the catalogue proper, it is a pleasure to find 



* See Bot. Gaz. 56: 143-152. 1913. 



