98 INTRODUCTION TO THE STUDY OF FUNGI 



in size and number until it disappeared. When the latter 

 condition occurred, all traces of the carbonisation of the soil 

 had long vanished, and it was overrun with docks (Rumex), 

 which superseded and replaced the Agaric. Whilst the 

 Agarics were in the ascendant, the soil was found, at all 

 periods of the year, plentifully traversed by mycelium. In the 

 case of Agaricus (Glitocybe) nebularis we have remembrance 

 of a mass of decaying leaves, which was undisturbed for 

 several years, and produced in succession for as many years in 

 the autumn good crops of the Agaric. The inference would be 

 that the mycelium was perennial, but it is not wholly conclusive, 

 since the germination of the spores of one season might also 

 form a new mycelium for the production of the next year's 

 crop. The generally-accepted theory of the growth of fairy 

 rings attributes their peripheral extension to the continued 

 outward growth of a perennial mycelium. Experienced Fungus- 

 hunters are well aware of the fact that, in the case of such 

 Fungi as Cortinarius triumphans and Agaricus {Amanita) 

 muscarius, they may be met with year after year in the same 

 spot, under the same birch tree, and often in company ; but 

 this, fact would not of itself demonstrate whether the appear- 

 ance was due to a perennial mycelium or the rejuvenescence 

 by means of germinating spores. It is not difficult to cause 

 the spores of Agarics to germinate artificially in a suitable 

 medium, but it is almost impossible to carry on the process to 

 the formation of a proper mycelium. This, however, proves 

 nothing as to what goes on in a state of nature, where the 

 conditions are such as not to be successfully imitated. We 

 may be certain that the hibernation in the Agaric does not 

 take place with the thin-coated spores, but with the mycelial 

 threads resulting from germination. In other orders of Fungi, 

 and in the Algae, the resting- spores secrete a thick rigid outer 

 coating, in which the hibernating season is passed, the eonidia 

 only, or such spores as germinate at once, having but a thin 

 envelope. It may be inferred, therefore, that whether the 

 mycelial threads are persistent from a previous season, or but 

 recently developed by germination of the spores, it is under 

 the form of mycelium, and in that form alone, that the winter 

 is passed. Experience has demonstrated that a keen winter, 



