PUFF-BALL FUNGL—GASTROMYCETES 159 



to the teeth of the endoperidium ; hut sometimes the spores 

 are expelled without extrusion of the spore-sac. In all 

 species every part of the plant, with the exception of the 

 spore-sac, is perfectly rigid and cartilaginous when dry, every 

 part except the inner surface of the endoperidium becoming 

 swollen and more or less mucilaginous when moistened. 

 The stem-like base increases in growth when the spores are 

 mature. 



In Battarrca De Bary has shown that the whole develop- 

 ment, up to the maturing of the spores, is passed while still 

 enclosed in the volva ; and when this is ruptured by elongation 

 of the stem, a portion of the volva is usually carried up on 

 the surface of the circular peridium, which is more or less 

 crescent -shaped in section (Fig. 67). Finally the peridium splits 

 along the margin, the upper portion falling away, and leaving 

 the spores exposed on the lower persistent part, from which 

 they are soon blown away. 



In Tylostoma also the differentiation of the gleba takes 

 place underground. When the spores are mature the stem 

 elongates. This elongation is due to increase in 

 length of the central portion, the outer or sheathing 

 portion being cracked transversely, one portion 

 remaining below and sheathing the base, the other 

 forming an abrupt termination of the base of the 

 peridium like a collar at the apex of the stem. 



One of the most interesting genera of the 

 stipitate forms is Podaxis, which is a native of warm 

 climates, being particularly associated with the 

 nests of Termites. In this genus Mr. Massee 

 contends that the spores are produced in sacs or f\\'\[y\ 

 asci, and infers that therefore they belong system- 

 atically to the Ascomycetes ; but with this inference 

 we do not agree. Although the spores are at first 

 enveloped in cysts, it by no means follows that ^m. 67.— 

 this establishes an affinity with Ascomycetes, but Battarrm. 

 only an analogy. 



The species of Podaxis bear an external and superficial 

 resemblance, in size and form, to unexpanded specimens of 

 Coprinus comcitus : the upper elliptical, spore-bearing capitulum 



