THE BEGINNINGS OF PLANT LIFE 
The algal types try to adjust themselves first to tem¬ 
porary and then to permanent land life. They seem to 
have tried a variety of adjustments. Some of them 
adopted one of these adjustments, discarded the others, 
and became mosses. Others became pteridophytes in the 
same process, and others may have become gymnosperms. 
It is not a case of mosses developing from algae and 
pteridophytes from mosses and so on up the scale of 
plant life. All developed simultaneously from a com¬ 
mon beginning, the algae. Already a number of sub¬ 
divisions of the pteridophytic group, for instance, had 
originated at an early date. In these subdivisions it 
may have happened that some algae specialized along 
the lines of ferns, others along the lines of club-mosses, 
while others became horsetails. Probably a great many 
different types originated almost simultaneously from 
a variety of algal types. There is always a multiplicity 
of origins, just as among the higher animals some rep¬ 
tiles became mammals, and others became birds. 
The same new type, genus, or species, may even have 
developed simultaneously in different places from different 
plants. A species or a genus or a family does not neces¬ 
sarily go back to one common origin; it may spring from 
several sources. It is well to keep in mind the fact that 
Nature is enormously resourceful, and that different 
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