5 8 RESEARCHES ON FUNGI 



in respect to their direction of growth, by both gravity and light. 

 The branches grow in the dark in curves which take the most 



Fig. 20. — Fruit-body of Polyporus squamosus developed on a log in entire 

 absence of light, three weeks. old. It is branched and sterile: there are 

 no signs of a pileus. Cf. Figs. 1, 4, and 5. Reduced to f natural size. 



varied directions in space, and show no definite indications that 

 they are either positively, negatively, or transversely geotropic. 



Light from a small hole cut in the dark-room door was allowed 

 to fall obliquely on to the log upon which some almost fully 



