130 FUNGI. 
those which influence the dispersion of the minute sporidia from 
the terminal cysts. Probably they are more perennial in their 
character, and are assimilated more to the oogonia of Cystopus 
and Peronospora, being rather of the nature of resting spores, 
inasmuch as the same threads usually bear the terminal fruits. . 
THECASPORES is a term which may be applied generally to all 
sporidia produced in asci, but these are in turn so innumerable 
and variable that it will be necessary to treat of some of the 
groups individually. The Thecaspores, for instance, of the Tu- 
beracei offer several features whereby they may be distinguished 
from other thecaspores. The asci in which these sporidia are 
generated mostly partake of a broadly saccate, ovate form. The 
number of sporidia contained in an individual ascus is usually 
less than in the majority of the Ascomycetes, and the sporidia 
approximate more nearly to the globose form. Usually, also, 
they are comparatively large. Many have been figured by 
Corda* and Tulasne.t Three types of spores may be said to 
prevail in the Tuberacei: the smooth spored, 
the warted or spinulose, and the areolate. The 
first of these may be represented by the Sve- 
phensia bombycina, in which the globose 
sporidia are quite smooth and colourless. 
Fis. 64.—Sporidium of The warted sporidia may be observed in 
Ee Gane verrucosa, the spinulose in Zuber 
nitidum, and the areolate are present in Tuber estivum and 
Tuber excovatum, in which the epispore is divided into polygonal 
alveoli, bounded by thin, membranaceous, pro- 
minent partitions. This form of sporidium is 
very beautiful. In all no special provision is 
-made for the dissemination of the sporidia, 
as, from their subterranean habit, none would 
be ayailable save the ultimate dissolution 
Fic. 65.—Alveolats of the external jnteguments. As they are 
sporidium of Tuber oreedily devoured by several animals, it is 
possible hat they may be dispersed through the excrements, . 
* Corda, ‘‘Icones Fungorum,” vol. vi. Prague, 
+ Tulasne, ‘Fungi Hypogei.” Paris. . 
