154 



RESEARCHES ON FUNGI 



a pileus including some uninjured spines were placed in a closed 

 moist compressor cell, and various basidia were watched with the 

 microscope. Owing to the crowding of the basidia, the small size 

 and slow development of the spores, and other difficulties, a long- 

 continued study of the sections was required before any successful 



observations could 

 be made. The 

 investigation of 

 Hydnum imbrica- 

 tum cost six hours 

 and that of H. 

 ferrugineum four 

 hours, whereas 

 similar investiga- 

 tions upon Agari- 

 cineae can usualty 

 be brought to a 

 successful conclu- 

 sion in less than 

 an hour. 



The illustrations 

 of Hydna here 

 provided show 

 fruit - bodies of : 

 (1) Hydnum re- 

 pandum which 

 commonly occurs 

 in leaf-mould in 

 woods in Europe and North America and has a central stipe and 

 rounded pileus like a Mushroom ; (2) Hydnum septentrionale 

 which occurs upon tree-trunks in Scandinavia, Canada, and 

 the United States, but not in p]ngland, and which in general 

 form resembles a dimidiate Polyporus ; and (3) Hydnum erinaceus 

 which grows attached to logs of wood, etc., in Europe and 

 North America, and has a relatively reduced pileus-flesh and 

 very large and conspicuous spines. Some remarks upon the 

 great size of the fruit-body masses of H. septentrionale and upon 



FIG. 54. Hydnum septentrionale Fr. Transverse section 

 through two imbricated pilei of the fruit-body 

 mass shown in Fig. 53. The hymenial teeth are 

 positively geotropic and look vertically down- 

 wards. The space between the two pilei permits 

 of the wind sweeping away the spores falling from 

 the teeth of the upper pileus before they can settle 

 on the top of the lower pileus. The longest teeth 

 are 1*1 cm. in length. Natural size. 



