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 
