ZVGOSPOREM. 



26s 



weft an area of several square centimetres. The mycelial filaments grow on organic 

 substrata, such as fruits, bread, glue, or even on saccharine fluids or dung, absorbing 

 their nutriment from them ; many species even grow parasitically on others nearly 

 allied, exhausting the contents of their cells through peculiar feeding organs, the Haus- 

 toria (see Fig. 175 h). 



The non-sexual propagation of the mycelium may continue through an endless 

 number of generations, until the conditions are favourable for the formation of con- 

 jugating organs, i.e. for sexual reproduction. The conidia arise in two different 

 ways: — In the family of Mucorini stout branches grow from the mycelium erect 



I 



Fig. 174.—^ Mycelium three days old of Phyconiyces nitetts grown in a drop of 

 gelatine with a decoction of plums ; the finest ramifications are omitted ; g the conidio- 

 phore ; A a conidiophore of Mucor Mucedo in optical longitudinal section ; C a germi- 

 nating zygospore of Mucor Mucedo z ; the germinating filament /6 is here putting out a 

 lateral conidiophore^. D Free conjugating branches 6 b, the extremities of which a a 

 have not yet coalesced, but are separated by a septum ; the zygospore results from the 

 coalescence. of the cells a a. {A,C, D after Brefeld ; B from nature.) 



into the air, reaching a height of several centimetres, and at length swelling up at 

 the summit into a sphere (Fig. 174 B, g). Within this sphere are formed a number of 

 round endogonidia, which become free by the rupture of the wall, germinate at once, 

 and reproduce the mycelium. In a second family, the Piptocephalidae, the conidia 

 are also produced on erect stalks, but these stalks branch copiously near their summit, 

 and form numerous conidia (stylogonidia) by abstriction at the extremity, which 

 produce a mycelium just as in the previous case. Besides these normal non- 

 sexual reproductive organs, the mycelium also frequently produces gonidia of 



