28 RESEARCHES ON FUNGI 



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





FlG. 4. — Fruit-body of Poli/porus squamotus 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. 



IT 



Then the ratio - gives the increase of surface of the hymenium 



