226 ROMANCE OF LOW LIFE AMONGST PLANTS. 



cortical portion, the volva or peridium, composed of 

 three layers, viz., an outer firm skin, or membrane, 

 which is the external peridium ; an inner thin mem- 

 brane which is the internal peridium ; and an inter- 

 mediate, much thicker, layer of translucent, pale 

 yellowish-brown gelatinous material, which is the 

 gelatinous layer. At the base there is a cup-shaped 

 portion which supports the stem, and is continuous 

 laterally by its margin with the layers of the peridium, 

 and below with the mycelium. (2) A central medul- 

 lary portion, composed of two very different struc- 

 tures ; firstly, the gleba, or spore-bearing part, which 

 forms a hollow conical cap, lying within the inner 

 peridium, and surrounding the upper portion of the 

 stem, to the apex of which it is firmly attached. Its 

 outer surface bears the hymenium, and is honey- 

 combed by a large number of irregular chambers, or 

 depressions, in which the mass of spores is lodged. 

 Secondly, the stem, consisting of a cylinder, whose 

 walls at this stage are firm and solid-looking, and 

 composed of a multitude of small, vertically com- 

 pressed cavities, filled with jelly. 



The volva is at first concealed beneath the surface 

 of the soil, but towards maturity it breaks through 

 the ground, and the exposed part gradually becomes 

 conical and finally ruptures, the stem rapidly lengthen- 

 ing and elevating the gleba in the air. These pheno- 

 mena depend upon a peculiar mechanical change 

 which occurs in the stem. The gelatinous contents 

 of the flattened cavities disappear, and they become 

 excessively dilated, the previously compact stem 

 increasing threefold or fourfold in magnitude, and 



