CLASSIFICATION 391 



pocket lens ; in fact, without a lens the characters even of generic 

 rank cannot be seen in many instances. 



In the Thelephoracece it will be remembered that the hymenium 

 is in all typical forms quite smooth or devoid of .any specialized 

 projections or outgrowths of any kind, only in the genus Crater ellus 

 the hymenium shows vague, vein-like wrinkles or folds, thus form- 

 ing a transition to the present family through the genus Phlehia, 

 where the hymenium is distinctly wrinkled or veined, and in some 

 species the slight veins or folds are covered with minute warts. 

 From this starting point the warts on the hymenium gradually 

 increase in length until the crowded long spines of Hydnimi is 

 reached, which is the extreme of hymenial evolution attained to 

 in the Hydnacea^. 



In like manner there is a perfect sequence in the evolution of the 

 hymenophore from the primitive crust-like patches of Grandinia, 

 closely adherent throughout to the substance upon which they are 

 growing, through species of Irpex, where one edge of the sporo- 

 phore is free from the matrix, and more or less reflexed, until 

 central-stemmed species of Hydnum furnished with a cap, resem- 

 bling a toadstool in build, is reached. 



Key to the Genera 



* Spines sharp- pointed. 



Fungus with a cap and central stem, dimidiate or forming an 

 inseparable crust on wood ; spines sharp-pointed, free from each 

 other at the base. Hydnum. 



Forming crust-like patches on wood ; spines springing from 

 wrinkles that form an irregular network on the surface of the 

 hymenium. Irpex. 



Forming a crust, texture of hymenium from which the spines 

 spring, loose and fibrous ; spines minute. CaldcsicIIa. 



Forming a thin crust, covered with very minute spinules. 



Knciffia. 



Spines very slender, apparently springing directly from the wood, 



Mucronclla. 



** Outgrowths of the hymenium either suhcylindrical, blunt tuber- 

 cles or flattened, tooth-like, irregular plates. 



With a cap and more or less central stem ; teeth flattened, 

 irregular. Sistotrcma. 



Forming crust-like patches on wood, outgrowths of liymenium 

 subcylindrical, coarse, blunt-ended. Radulum. 



*** Outgrowths of hymenium consisting of crowded, minute warts. 



Forming thin crusts on wood ; hymenium covered with minute 

 rounded warts. CratuUiiia. 



Forming thin crusts on wood ; hymeniuni coxcrcd witli minute 

 warts, the tips of which are fringed witli spinules. Odoniia. 



