THE MOULD-FUNGI. 89 



sporium swells and emerges (/), and elongates itself to a 

 germ tube, which quickly develops conidiophores. 



Penitillium possesses the power of secreting an invertive 

 ferment, which is able to convert cane-sugar into other sugars. 



3. EUROTIUM ASPERGILLUS GLAUCUS. 



The development of this fungus was first thoroughly 

 described by the celebrated de Bary. It forms a fine felty, 

 greyish or greyish-green covering on various materials, and is 

 able to grow with the greatest luxuriance on green malt. 



The mycelium consists, as in the case of Penicillium, of 

 fine transparent and branched threads, provided with trans- 

 verse septa. Some of the hyphal threads are thrown up 

 perpendicularly, are thicker than the rest, and very rarely 

 branched or divided by septa. Their upper ends swell to 

 spherical flask-shaped heads (c) ; and these throw out from 

 their entire upper portion radially divergent papillae of an 

 oblong form ; these sterigmata then .throw out at their apex 

 small round protuberances, which are attached to the sterig- 

 mata by greatly contracted bases, and after some time are 

 defined from the former as independent cells (spores, or 

 conidia). Below the base of the first spore, a second begins 

 to form from the crown of the sterigma, and pushes the first 

 upwards ; a third then forms, and so on. Each sterigma thus 

 carries a chain of spores, the youngest of which is closest to 

 the sterigma. This occurs at the same time over the whole 

 surface of the enlarged ends of the conidiophore, which is 

 thus finally covered with a thick head of radially-arranged 

 chains of spores. These masses of spores form the greyish - 

 green dust which covers the mycelium. 



Finally, the conidia separate from one another ; they have 

 then a warty appearance on their outer surface. These 

 small bodies are able to germinate (p) directly after they 

 have become detached, and quickly develop a new mould- 

 fungus; on this fact depends the rapidity with which the 

 plant spreads. Under certain conditions, which are not yet 



