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Young World
Wedded to water
MADHAV GADGIL
Time has come, that thallus said
To leave this world so wet,
To rise and shine and seek the sun
My crown of frond's all set!
Tree ferns are relics of an ancient age; close kin of the earliest of trees to clothe the land. These appeared as early as thirty-six crore years ago, just nine crore years after the first tiny plants colonised the land. Indeed, the thallus phase of the ferns resembles these early land plants. These small flat thalli grow out of spores sperms that must swim through a film, of water to fertilise the eggs that then grow into adult ferns. Three ferns possess a number of innovations that go to make a tree: a covering resistant to loss of water, tubes to conduct water and nutrients, support tissue to grow tall to compete for light, and flat leaves to soak up the light. But they still need water to breed, and they cannot branch so that their crowns remain straight and narrow. As a result, they are now confined to just a few habitats, such as the wet valleys of the Western Ghats.
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