26 BRITISH FUNGI 



group belong the puffballs, wliere the whole of the hymenium or 

 spore-bearing surface is enclosed in an unbroken wall, corresponding 

 to the universal veil present in some agarics, until the spores are 

 quite mature, when the surrounding wall, or peridiiim as it is called 

 in this group, opens in some special way to admit of the escape into 

 the air of the spores. The common stinkhorn also belongs to this 

 group. 



The two primary groups of tlie Hasidiomycetes are, in turn, 

 broken up into several distinct families, of which the following are 

 included under the H^-menomycetes. 



Agaricace^ 



This family is characterized by the hymenium or spore-producing 

 portion of the fungus being produced on gills or lamelhe. It is the 

 most highly organized family included in tlie Hymenomycetes, 

 whether viewed from the point of view of protection of the essential 

 portion of the fungus, or from the standpoint of spore production 

 and dispersion. The hymenium being formed under the shelter 

 of the cap, which acts as an umbrella, protects the spores until readv 

 for dispersion. The arrangement of tlie gills insures the production 

 of the greatest number of spores with the least expenditure of 

 material, and the small size of the spores insures their wide dis- 

 persion by wind and other agencies. 



In the great majority of agarics the entire fungus rapidly de- 

 composes and disappears, after the spores have been shed, and in 

 all such the gill structure shows the highest phase of development 

 to which the agarics have attained ; that is, the plates or lamelke 

 are so arranged that the greatest possible number is packed in a 

 comparatively small area, yet perfecth' free from each other. In 

 such genera as Marasmiiis, the entire consistency of the fungus is 

 tougher, and does not perish so quickly, and the gills, instead of 

 being quite free from each other, are connected by transverse 

 ridges or veins, which just shadows in the porous nature of the 

 hymenium characteristic of the next family, Polyporaceae. Passing 

 on to such genera as Lentimts and Lenzites, we find the substance of 

 the fungus becoming cork}' and woody, and the gills so connected 

 by transverse ridges as to appear as much porous as gill-like in 

 structure ; and if we take into consideration tlie fungi of the world 

 at large, it becomes a matter of personal opinion as to whether such 

 genera occupying the border-line, should be included in the Agari- 

 caceas or the Polyporaceae, from which the first-named family 

 probably evolved. 



Polyporaceae 



The characteristic mark of this family consists in the porous 

 nature of the hymenium, which in the most typical form suggests 

 the idea that the entire surface had been perforated with pin-pricks 

 closely crowded together. The little holes or pores are sometimes 



