THE MOULD-FUNGI. 105 



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 transverse 

 septa. Some of the hyphal threads are thrown up perpendicu- 

 larly, 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 papilla? of an oblong form ; these 

 sterigmata then throw out at their apex small round pro- 

 tuberances, which are attached to the sterigmata by greatly 

 constricted 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 sufficiently known, 

 but which in every case appear to be connected with a free 

 supply of nutriment, the mould develops perithecia. These 

 appear at first as tender branches, which, at the termination 

 of their longitudinal growth, begin to twine their free ends in 

 the form of a spiral of four to six turns (/) ; the threads of the 

 spiral gradually approach nearer together, until finally they 

 are brought into contact, so that the entire end of the 



