PUFF-BALL FUNGI— GASTROMYCETES 



155 



Fi(i. 65. — Lycuperdon, with 

 sterile base and columella. 



peridium (Fig. 65). This columella is only a continuation of the 

 spongy base in Lycoperdon, but in Diplodcrma it is hard and 

 woody. In some species of Geasfpr 

 the columella is distinct and club- 

 shaped, extending half-way up, with 

 the threads of the capillitium radiat- 

 ing towards the periphery. De B<iiy 

 has described the complex peridium 

 of Geaster in the following terms : — 

 " Geaster hygrometricus is up to the 

 period of perfect maturity a roundish 

 body, which may be of the size of a 

 hazel-nut, and remains beneath the surface of the ground. 

 Six layers may be distinguished in the peridium in a vertical 

 longitudinal section a sliort time before the compound sporo- 

 phore is mature (Fig. 66). The outermost layer is of a brownish 

 colour, flaky and fibrous, and is continued on one side into the 

 mycelial strands which spread through the soil, and on the 

 other passes into the second layer ; a thick, stout, brown 

 membrane entirely covering the compound sporophore. This 

 is followed towards the inside by a white layer, which is 

 more largely developed at the base of the compound sporo- 

 phore than elsewhere, and is immediately continuous at that 

 spot with the inner peridium 

 and the gleba. Both of these 

 last-mentioned layers are formed 

 of stout, closely -woven hyphae 

 running in the direction of 

 the surface, and may be com- 

 bined under the name of the 

 fibrillose layer. The inner of 

 the two is lined on the inside 

 by the collenchyma layer, ex- 

 cept where its basal portion passes into the gleba. This 

 layer is cartilaginously gelatinous, and consists of hyphal 

 branches of uniform height, connected together, without 

 interstices, which are placed palisade -like vertically to the 

 surface, and are bent as they spring from the hyphae of the 

 fibrillose layer. The strongly-thickened stratified walls of the 



Fig. 6Q.— Geaster. 



