28 RESEARCHES ON FUNGI 



fruit-body, when gills, tubes, or spines have been removed. Let 



FlG. 4. Fruit-body of Polyporm squamosus nearly full-grown ; upper surface covered 

 with brown scales. The full length of the stipe is photographed. Photographed 

 by R. H. Pickard. natural size. 



H be the area of the hymenium upon the gills, tubes, or spines. 



TT 



Then the ratio gives the increase of surface of the hymenium 



