Tree Study 



793 



structures. When the pine forests on the shores of the Great Lakes are in 

 bloom, the pollen covers the waves for miles out from the shores. 



White pine. 



If we examine the growing tips of the pine branches, we find the leaves 

 look callow and pin-feathery. The entire leaf is wrapped in a smooth, 

 shining, silken sheath, at the tip of which its green point protrudes. The 

 sheath is tough like parchment and is cylindrical because the pine needles 



Yellow pine on the brink of the Li tile Yosemite Valley. 

 Photo by G. K. Gilbert. Courtesy of U. S. Geological Survey. 



