IF THIS AGED CEDAR COULD TELL ITS LIFE’S STORY, WE WOULD FIND IT FULL OF ROMANCE AND ADVENTURE
CHAPTER III
Migrations of Plants
“Race after race of leaves and men
Bloom, wither and are gone;
As winds and water rise and fall
So life and death roll on.”
We are so in the habit of thinking of plants as fixed and static things that it rarely occurs to us that they migrate over the earth’s surface quite as extensively as do men or animals.
While it is probably true that vegetation originated simultaneously at different points on the globe’s surface, not much observation is necessary to indicate that it does not always stay where it is put. Plants are peculiar and native to certain lands in a very definite way, but their love of adventure often carries them to the far corners of the earth. They are the most energetic and effective colonizers in existence. The complete history of plantdom would include the stories of invasions, conquests and revolutions quite as stirring as anything in human annals.
If it is absorbing to follow the racial movements of man, ancient and modern, it is equally fascinating for a lover of plants to investigate their migratory habits. We have exact records of many of their travels and can make interesting conjectures about the rest.
To a layman, the present distribution of plants may seem chaotic. He reads that certain families are natives of Europe and Australia, or North America and Africa and are absent from all intervening countries. The Alpine species Primulas and Saxifrages are common to both the Arctic and the Antarctic. There are fifty-eight European and New Zealand species which are identical. The British Grass Poa Annua is also found in the Andes of Brazil. Through what thousands of years of change and evolution have these things come about! Yet the results are no more complex than was the filling of America with its mixed and conglomerate human population.
In a general way, there is a measure of fixity to plant distribution. Certain plants have elected the tropics as their home; and only under the greatest stress of circumstance can they be induced to go elsewhere.
Tropical heat and moisture make for luxuriance of vegetation. There is a much greater variety there than in the North. Woody Vines climb the tallest trunks, where they intermingle their leaves and blossoms with those of their host. Gorgeous Air Plants beautify and perfume the forest. Stately Palms wave magnificent bouquets of pendulous fronds.