112 A PLAIN AND EASY ACCOUNT 



which, nevertheless, none but a novice would confound 

 them. 



In the manufacture of the handsome Tunbridge-ware 

 a variety of wood is employed under the name of green 

 oak. Although of a mineral-green colour, this is the 

 ordinary British oak ; but the alteration which it has 

 undergone is due to the presence of a fungus. A hand- 

 some little species resembling a Peziza (Helotium ceru- 

 ginosum) traverses with its mycelium the whole fabric 

 of such wood, and these minute threads give their green 

 tint to the timber. When examined under the micro- 

 scope, the beautiful network of the green mycelium is 

 distinctly seen. This fungus attacks the fallen oak- 

 branches, and the timber affected by it is therefore 

 generally small in diameter ; but, from the minute size 

 required in the manufacture for which it is employed, it 

 answers equally with the largest. Green wood is so 

 exceedingly uncommon that, although in a state of 

 decay, the green oak becomes of a marketable value. 

 The little green open cups of this Helotium are not so 

 commonly met with as the timber showing traces of its 

 mycelium. 



So long since as the time of Pliny and Dioscorides, 

 the truffle seems to have been known and appreciated. 

 There are numerous species, and several of these are 

 indigenous to Britain. In form and habit they differ 

 considerably from the majority of fungi, having the 

 appearance of rough, dark-coloured, warty nodules, 

 occasionally nearly as large as the fist, and which are 

 found buried beneath the surface of the soil (PI. 23, fig. i.). 



