1903-4. | How Puant LIFE Is DISTRIBUTED IN CANADA AND WHy. 29 
prevent them from too quickly reaching the ground when they fall at 
maturity, but also afford a better opportunity to the wind to carry them 
to great distances. And these distances are not to be measured neces- 
sarily by an acre lot or even the breadth of a township. Volcanic dust, 
forced from a volcano during eruption may float through the atmosphere 
for many hundreds of miles before descending. What may not be pos- 
sible with light seeds when a gale of wind prevails ? The great range of 
so many sub-arctic and boreal lichens, also found on most high summits 
in middle and even southern temperate countries, seems likewise, an evi- 
dence of the power of the winds in carrying spores to enormous distances. 
The question, however, here naturally suggests itseli—Why are 
many species of wide range, reaching from one side of the continent to 
the other, whilst so many others are circumscribed in area? All of the 
general causes indicated have been important factors in the extension 
of the range of plants, but there is another and general conclusion, the 
drawing of which analogy warrants. It may be regarded as the innate 
aggressive energy in such species or the lack of this energy. Every 
plant may be said to have an area where its numbers and its life energy 
are at the maximum. Outside of this area, the individuals are found, 
diminishing in numbers as they extend, until they finally cease on 
every side. The growth, again, of each individual plant, has its birth 
in the swelling seed, its maturity when it expands its flower, and its 
death when, after ripening its seeds, it withers and decays. Similarly, 
each species, as such, has had its beginning in past ages, in the develop- 
ment and permanency of a well defined variety formed from an already 
existing species. This new species, thus formed, would, in the course 
of downward geological time, reach its highest stage of existence as a 
species; its period of most active growth and of largest area of distribu- 
tion, when its ability, under new surrounding conditions, to give rise 
to further new species, is greatest. Finally, such species has, in down- 
ward geological time, its period of decline, when with perhaps changing 
environment, its innate energy as a species is diminishing and its areas of 
distribution being gradually curtailed, until extinction comes, leaving 
to the paleobotanist the duty of revealing its story when he discovers 
the remains in the clay nodule or the hardened rock. Applying this 
idea, the older existing species, which are at their maximum of activity, 
would, with the greater opportunities which in time they had had, have 
naturally a wider range, under the same set of circumstances, than those 
which were of more recent creation. Others, again of the older species, 
would have passed their maximum of energy and, even though wide of 
range, would, in each passing century, become more rare. The species 
of newer creation would, on the other hand, be gradually extending 
their range wherever circumstances of climate and situation admitted, 
