•424 STRUCTURE AND LIFE HISTORIES 



pollen-grains are, of course, blown hither and thither with 

 every breeze, and millions of them never reach a carpellate 

 cone. The writer once found an accumulation of pine 

 pollen in a desk drawer that; had remained constantly 

 closed (but in the vicinity of a pine tree) during the 

 season of pollination. A microscopic examination of 



Fig. 314. — Shedding of pollen from a young pine tree. Note the cloud 

 of pollen at the left, caused by shaking the tree. 



dust from ledges, indoors and out, at the pollen season, 

 will usually disclose one or more pollen-grains of pines 

 and other species. 



377. Pollen and Coal-formation. — A microscopic ex- 

 amination of muck from the bottom of almost any in- 

 land lake will disclose the fact that it contains millions of 

 pollen-grains of various cone-bearing trees, and spores of 



