140 INTRODUCTION TO THE STUDY OF FUNGI 



and the pores shallower and irregular. The latter genus 

 leads to Merulius, with its soft, waxy hymenium, the surface 

 of which is reticulated with .obtuse folds, forming irregular 

 areolae, the folds sometimes rather toothed. This is possibly 

 the lowest and most imperfect of the Polyporei. A recent 

 genus, Campbellia, is a higher development, with a pileus and 

 stem and more distinct pits or pores. Porothelium has the 

 habit of Porta, but the tubes are more scattered, reduced to 

 papillae, and at length pierced and open. Some authors add 

 Solenia to the Polyporei, whilst others have associated it with 

 Cyphella in the Thelephorei. 



The third primary group of the Hymenomyceteae is the 

 Hydnei, in which the gills of the Agaricineae and the tubes of 

 the Polyporei are replaced by teeth or spines, the outer surface 

 of which is clothed with the hymenium, which is therefore 

 wholly exposed. There is at no time, and in no known species, 

 any kind of veil covering the hymenium in its early stage. 

 The most typical genus is Hydrnm, which remains much the 

 same as Fries left it, although there has been more than one pro- 

 posal to split it up into smaller genera (Fig. 54). In the stipitate 

 species some have a central stem, others a lateral stem, and in. 

 others the common stem is 

 branched and subdivided, but 

 the pilei are imperfect. In 

 another section there is no 

 stem, but the pileus is sessile 

 or imbricate, and there are a ) 



large number of species which r 



are as entirely resupinate as in O^ 



the porous genus Poria, to Q 



which this section is analogous. „ „. „ .. ,„ , , 



° Fig. 54. — Section of Hydnwm repanwwm. 



There is also considerable 



difference in texture, some being fleshy, others waxy or 

 leathery, and others becoming quite hard and corky. At 

 one time a gelatinous species was included, but this has 

 been removed on account of its affinity in fructification with 

 Tremella. The teeth are variable in length and thickness in 

 different species, but they agree in being more or less pointed 

 at the apex, and free from each other at the base. 



