SHADE TREE AND TIMBER DESTROYING FUNGI. 223 



ing the latest growth varies in color according to the time of col- 

 lection. When the marginal zone is young it is whitish or 

 yellowish in color, becoming reddish yellow or red later in the 

 season and having then a shining polished surface. The under 

 surface is yellowish white, and on bruising, the yellow color is 

 often more distinct. The pores of the under surface are just visi- 

 ble to the naked eye. On sectioning the fruit body the annual 

 layers seem quite distinct. 



82. Section of fruit body of Poly poms app/anatus, showing tube strata, 



The size and distinctness of these concentric elevations or 

 zones on the upper surface of the fruit body vary according to 

 the rapidity of growth. Where the growth is rapid the zones 

 are large and prominent on the fruit body, increasing rapidly in 

 size each year. One fine specimen collected on a hemlock spruce 

 in the vicinity of Ithaca is 40 cm. broad by 25 cm. long, and is 

 only six or eight years old, there being apparently two imperfect 

 zones which may represent years of very slow and imperfect 

 growth. Of the six annual marginal accretions which are very 

 prominent the measurements are as follows: First, 4 cm.; 

 second, 6cm.; third, 3 cm.; fourth, 2.5 cm.; fifth, 3.5 cm.; 

 sixth,. 4 cm. The usual size of the annual zone is from 2 to 3 



