Recognize these leaves?
The species shown here represent many of the genera,
or kinds, of trees in the United States.
All these leaves make food for the tree, and leaf shape is important. For example, the narrow needles of a Douglas fir
can expose as much as three acres of chlorophyll surface to the sun. The
lobes, leaflets and jagged edges of many broad leaves have their uses,
too. They help evaporate the water used
in food-building, reduce wind
resistance--even provide "drip tips" to shed rain that, left standing,
could decay the leaf.
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