244 
Massee . — The Structure and 
peridium or outer wall of the puff-balls originate in a similar manner, and 
are not in any instance due to local growth of the cortex. Simultaneous 
with the differentiation of the cortex, the solid mass of the sporophore 
becomes pierced by numerous tortuous rifts or cracks, the walls of which 
gradually recede from each other and bear the asci, which project into the 
cavity. The general appearance of a section of a mature sporophore may 
be compared to a section of a nutmeg. From the first the sporophore con- 
sists of two distinct systems of hyphae ; one, the vegetative hyphae, go to 
form the peripheral portion of the sporophore, including the cortex, also the 
walls in the interior of the sporophore, whose free faces bear the hymenium. 
The second system of hyphae give origin to the asci alone. The com- 
ponents of this system have thinner walls, and are more slender than the 
vegetative hyphae, with which they grow intermingled until the free sur- 
faces of the internal cavities are reached, where they form a compact layer 
the free ends giving origin to a succession of asci. At what point, and 
under what conditions the two systems of hyphae become differentiated in 
the minute knob representing the future sporophore, is not known. When 
the spores are mature, the asci along with the hyphae belonging to the 
ascigerous system, deliquesce, leaving the framework composed of vegetative 
hyphae in a more or less moist condition for some time. This state of 
things is more marked in the descendants of the subterranean forms of the 
Basidiomycetes, the Gasteromycetes or puff-balls, which at a certain stage of 
development are completely waterlogged, owing to the liquefaction of the 
system of spore-producing hyphae. At a later stage the sporophore 
becomes dry, and contains a dense mass of powdery spores, characteristic 
of a ripe puff-ball. 
When mature, the sporophores of subterranean Fungi emit a powerful 
odour. From the standpoint of humanity, this odour is sometimes very 
agreeable, as in some of the edible truffles ; in many other species it is 
very unpleasant, resembling asafoetida, and other indescribable odours. 
From the standpoint of the fungus, these odours are of the nature of 
advertisements, indicating their whereabouts to rodents, by whom they are 
eaten, and the spores, after passing through the alimentary tract, are 
dispersed. 
The Tuberaceae are an ancient group of Fungi, as evidenced by their 
extreme simplicity of structure. In the most typical genera, as Tuber , 
Elaphomyces , &c., the sporophore has a perfectly continuous cortex, and 
the whole mass continues to increase in size for some time after the 
mycelium from which it originated, has disappeared. In the genus Terfezia 
the cortex is still continuous, but a basal portion is shadowed in, which 
remains in continuity with the vegetative mycelium until the spores are 
mature. Finally, in Genea , Ckoeromyces , &c., the mycelium remains 
adherent to the ascophore, and supplies it with food until the spores are 
