130 Postelsia 
in point of number of species by three dicotyle- 
donous families, the Rosace@ with 18, the Com- 
posite with 14 and the Saxijragacee with 12. 
Since grasses, sedges and rushes nearly always 
build compact groups or societies with numerous 
individuals, it follows that a considerable array 
of species of these types means a considerable 
occupation of the available ground. 
Among the dicotyledonous families, aside 
from those mentioned above, the Hricacee show 
g species, the Scrophulariacee 9, the Ranun- 
culacee 7 and so on in decreasing number. Of 
the 52 angiospermous families 18 are represented 
by but a single species each. 
In giving the above figures the writer is well 
aware that the attempts to convey an idea of 
the aspect of vegetation and the floral composition 
of a given region by means of statistics, and per- 
centages especially, are often misleading and many 
times prove good as useless. This is partly due 
to the fact that statistics and percentages, based 
on a bare enumeration of families, genera and 
species do not incorporate the right elements of 
proportion and color, and futhermore do not al- 
