SECT. m. FAIRY-RING AGARICS. 263 



so frequently seen in pasture lands. The fairy rings are 

 sometimes of very ancient date, and attain enormous 

 dimensions, so as to be distinctly visible on the side of 

 a hill from a considerable distance. It is believed that 

 they originate from a single fungus, whose growth ren- 

 ders the soil immediately beneath unfit for its reproduc- 

 tion. The spawn, however, spreads all around, and in 

 the second year produces a crop, whose spawn spreads 

 outwards again, for the soil behind forbids its return in 

 the opposite direction. Thus the circle is continually 

 increased, and extends indefinitely till some foreign 

 cause destroys it. The manure arising from the dead 

 fungi of the former years makes the grass vigorous 

 around, so as to render the circle visible even when 

 there is no external appearance of the fungus ; and the 

 contrast is often the stronger from that immediately 

 behind it being killed by the old spawn. This mode of 

 growth is far more common than it is supposed to be. 



The depth to which spawn penetrates and the rapidity 

 of its growth even in the hardest timber if exposed to 

 damp is quite astonishing. Instances occur in which 

 the spawn of dry rot not only enters wood, but pene- 

 trates solid structures of brick. It overcomes an im- 

 mense resistance. 



The genera of the Agaricini differ in substance ; some 

 are almost ligneous, others leathery or tough, occasion- 

 ally they are delicate and deliquescent, and although 

 most of them are entirely formed of cellular tissue, 

 the Lactarii and Russulse form remarkable exceptions in 

 having laticiferous vessels mixed with their cellular 

 structure. These vessels exist in all parts of the plants, 

 especially in the gills, where they give out the liquid on 

 the slightest touch. In the Russulse it is watery ; but in 

 the Lactarii, in which it is either mild or acrid, accord- 

 ing to the species, it is also of different colours, which 

 sometimes change their tint upon exposure to the air, 



