74 



MORPHOLOGY OF THE MUCORS. 



sugars, as was pointed out by 0. Wehmer (X.). In fact a patent 

 has been taken out in Germany (No. 91,891) for a process of 

 manufacturing citric acid by this means. The subject will be 

 mentioned again in a later chapter. 



§ 237.— Rhizopese. 



The higher, or carposporangial, group of the Zyuomycetes 

 a 234) can be divided into two families: Rhizopese and Mor- 

 tierellse. The former of these exhibits in a lower degree a 

 peculiarity more highly developed in the 

 second family, namely, the formation of an 

 integument, which surrounds the sporogenic 

 organ and therefore raises it to the dignity 

 of a true spore fruit. This second family 

 does not come within our purview, and all 

 that need be said about it is that all its 

 species, especially MortierelJa Ro4afiniskii — 

 which occurs on horse-dung and was discovered 

 and closely examined by Brefeld (IV. and 

 IX.) — -exhibit this method of fructification. 

 From the earliest period of their development 

 the zygospores are surrounded by a progres- 

 sively increasing network of hyphfe, which 

 spring from the adjacent mycelium, branch 

 extensively, and finally weave themselves 

 into a felted capsule surrounding the zygo- 

 spore on all sides. A less extensive develop- 

 ment is exhibited by the integument, which 

 endeavours to envelop the sporangium ; it 

 does not inci'ease to more than a dense cluster 

 of hyphfe, which surround the lower end of 

 the sporangiophore, without, however, being 

 able to reach the spoi'angium itself. A view 



S=i^J 



of this is given in Fig. 116. 



G. H5-M1ICUI 



Baiuier. 



tenuis 



Azygospores in various 

 stages of development. 

 {After Bainier.) 



stage 



In the family li/iizopece, however, which 

 comprises the two genera Rhizopus and 

 Abs/dia, this integument of the zygospores 

 is either absent {Rhizojnis) or only slightly 

 developed (Ahsidia), being arrested at the 

 of spiny processes protruding from the suspensores. 

 The special position of this family, outside the exosporangial 

 Zycjomycetes (§ 234), forming as it does the connecting link 

 between them and the MorfiereJ/a, cannot therefore be founded 

 on this indefinite characteristic of integumentation, but rather 

 depends on the property it shares with the family just men- 

 tioned, namely, the development of stolons and the i-esulting 

 peculiar conformation of the thallus. Whereas in the Mticorete^ 



