THE FUNGI 235 



TYPE XX. SPH^EROTHECA CASTAGNEI 



We now come to the higher Fungi, an immense 

 group of plants, which have become completely adapted 

 to every conceivable variety of parasitic and saprophytic 

 life, and no longer show any clear trace of affinity with 

 the Algse. While differing among themselves in every 

 other respect, they agree in possessing a septate, multi- 

 cellular mycelium, with apical growth of the hyphse of 

 which it is built up. 



Our present type is one of the simplest representatives 

 of the great family of the Ascomycetes, which are 

 characterised by possessing sporangia of very definite 

 size and form (called asci), in the interior of which a 

 definite and usually small number of spores are pro- 

 duced, the number being regularly some multiple of 

 two. In this respect, as in many others, they differ 

 from the Phycomycetes, where, as we have seen, the 

 number of spores formed in a sporangium is quite 

 indefinite, and often very large. It is, in fact, still an 

 open question whether the ascus can be regarded as 

 truly homologous with the sporangium of the lower Fungi. 

 The whole problem of the real relation of the Ascomycetes 

 to the simpler families of Fungi is still unsolved. 



We will proceed at once to the description of our 

 type, which will serve to give us an elementary idea of 

 the main facts in the structure and development of this 

 important and difficult group of plants. 



1. STRUCTURE 

 The species of Sphcerotheca and its nearer allies (form- 



