Metaphyta Penicilltum. 



95 



Peniciilium glaucum. 



at once a series of threads or elongated cells springing verti- 

 cally from the thallus into the air and bearing at their free 

 ends many strings or chains of minute rounded greenish 

 bodies, commonly known as spores. More careful exami- 

 nation shows that these spore-bearing filaments are simply 

 modified cells or threads of the thallus (fig. 27). Apparently 

 any cell, may give rise to a filament, which, when it reaches a 

 certain size, begins to branch at its free termination. The 

 successive stages in that division will be best understood by 

 a study of the figure (fig. 



27). The terminal Cells, FlG * ^.-GERMINATION OF SPORES OF 



after the branching has 

 sufficiently progressed, 

 bud off parts of them- 

 selves, the youngest 

 buds being those near- 

 est to the parent cell. 

 This budding is a purely 

 vegetative process, and, 

 though the buds at first 

 remain attached, they 

 are very soon set free 

 and blown about in great 

 numbers. Each bud or 

 spore consists of a very 



faintly yellowish-green cell-wall and colourless protoplasm. 

 A nucleus is said to be present, but it is not easily seen 

 without the assistance of reagents. 



If sown in or on a suitable medium, the spore begins to 

 germinate. At one or more places on the spore wall a 

 bud appears, which develops into a much elongated thread 

 not unlike one of the threads of the parent thallus (fig. 29). 

 The filament afterwards divides, and, alone, or in company 

 with filaments formed by other spores, forms a felt-like 

 thallus, like that which originally produced the spores. 



