150 



RESEARCHES ON FUNGI 



Thelephoreae the reader should consult the references given in 

 the Index. 



In what follows, on account of the fact that several well-known 

 Hydiieae, e.g. Hydnum repandum, greatly resemble terrestrial 

 Agaricineae in their general form, I shall treat of the Hydneae 

 before the Tremellineae. 



Spore-discharge in the Hydneae. The Hydneae are characterised 



FIG. 51. Hydnum repandum, a terrestrial Hydnum with a centric 

 stipe. Its hymenial spines are positively geotropic and 

 point vertically downwards. Photographed in leaf-mould 

 at Epping Forest, Essex, by Somerville Hastings. About 

 f natural size. 



by having the under sides of their pilei produced into sharply 

 pointed spinous processes (Figs. 51, 53-55). These processes, just 

 like the gills in the Agaricineae and the tubes in the Polyporeae, 

 serve to increase the surface area of the under side of the pileus 

 and therefore also the area of the hymenium which covers it. 

 Thus the spines, just like gills and tubes, serve to increase the 

 number of spores which a pileus of any given size is able to develop. 

 The spines of Hydnum repandum (Fig. 51) and of other Hydna 

 with centric stipes, like the tubes of the Boleti, begin their develop- 

 ment before the pileus expands and grow out perpendicularly 

 from the under surface of the pileus-flesh. The expansion of the 



