ORIGIN OF PLANTS 
turing starch by photosynthesis, spreading out 
into thin layers in order to present the greatest 
possible surface. 
These lower land plants retained and still 
retain some characteristics of their aquatic 
ancestry, notably swimming spore cells, as in 
the Mosses. ‘The formation of rigid cellulose 
about vegetable cells stops their movement, ex- 
cept when cilia or projections of protoplasm 
extend through openings in the cell walls. The 
Liverworts were probably among the first real 
land plants: their spores are non-motile and they 
have a massive, foot-like organ for the absorp- 
tion of water. 
To the liberality of Nature we must ascribe 
the development of the law which ties the plants 
to the soil. They started out as animals, but 
enjoyed such an abundance of food that it be- 
came unnecessary for them to go in search for 
it. Water and carbon dioxide, which formed 
their principal means of subsistence, were all 
about them; they settled down to a life of quiet 
ease. When Corals, Sponges, Oysters and other 
lower animals are similarly situated, they be- 
come as firmly rooted as any plant. Moreover, 
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