OF CERTAIN TERMITE NESTS. 215 



joined to the stem by a projecting collar or are continuous with 

 it where they merge into one another. 



The irregularity of the ring will be seen from the figures. 

 In some instances the outer layer divides into fibres so that 

 the expanding agaric appears to have an arachnoid veil. 

 In one case , where the agarics grew through a gravelled path . 

 fragments of the pileus and gills remained attached to the ring. 



These two agarics are apparently quite distinct, and it is 

 therefore not surprising that the second was placed by Berkeley 

 in another genus under the name Armillaria eurhiza. But 

 except for the ring there is nothing to distinguish them in the 

 parts which appear above ground : they are identical in size, 

 shape, structure of pileus and gills, size and colour of spores , &c. 

 Both too have the curious base of sclerenchymatous cells and 

 a cartilaginous 'universal veil. The colour of the pileus is 

 usually paler in the Armillaria form , but this is easily explain- 

 able. It is quite clear that the two are merely forms of the 

 same species. Under certain conditions, the original mound of 

 hyphas acquires a cartilaginous coat when it is only about 5 mm. 

 high, and there then results the Armillaria form in which the 

 universal veil clearly extends as a thick covering down to the 

 comb. More generally, however, the universal veil is not de- 

 veloped over the part in the comb chamber : the mound of hy- 

 phse produces at its apex a thin black cord which penetrates the 

 soil, and the development of the pileus takes places in a carti- 

 laginous covering in the earth above the chamber ; the mound 

 of hyphse at the base lacks this covering or shows only a 

 slight tendency towards the production of it. The presence 

 or absence of a ring is a more or less accidental phenomenon 

 brought about merely by a difference in the point of dehis- 

 cence of the universal veil, and we find accordingly that the 

 Pluteus and Armillaria forms are linked by specimens possess- 

 ing the ring of the latter and the black rooting base of 

 the former. 



It is noteworthy that while only one black-stalked agaric 

 develops out of the large number of mounds of hypha? which 



9(8)06 (1«) 



