GllOWTH OF FUNGI. 



41 



common in autumn on pears, apples, and other fruit, and fre- 

 quently while yet hanging on the tree. 



In the fields we see this tendency illustrated by the forma- 

 tion of fairy rings, which have for a long time puzzled philo- 

 sophers, and are not without their difficulties now. These 

 rings are sometimes of very ancient date, and attain enormous 

 dimensions, so as to be distinctly visible on a hillside from a 

 considerable distance. It is believed that they originate from 

 a single Fungus, whose growth renders the soil immediately 

 beneath unfit for its reproduction. The spawn, however, 

 spreads all round, and in the second year produces a crop, 

 whose spawn spreads again, the soil behind forbidding its 

 return in that direction. Thus the circle is continually in- 

 creased, and extends indefinitely till some cause intervenes to 

 destroy it. If the spawn did not spread on all sides at first, 

 an arc of a circle only is produced. The manure arising from 

 the dead Fungi of the former years makes the grass pecu- 

 liarly 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 behind being 

 killed by the old spawn. This mode of growth is far more 

 common than is supposed, ami may be observed constantly in 

 our woods, where the spawn can spread only in the soil or 

 amongst the leaves and decaying fragments which cover it. 



The rapidity with which spawn penetrates, and the depth 

 to which it enters, is often quite surprising. The most solid 

 timber, in a few months, when exposed to the weather and 

 in a damp situation favourable to the development of Fungi, 

 will sometimes show unequivocal traces of spawn. I have 

 seen, for instance, elm trunks Mhich were perfectly scuiid 

 when felled, penetrated by the cud of the second year with 

 spawn to within a few inches of the centre; and in this case 



