340 MORPHOLOGY OF THE ASPERGILLACE^]. 



together at first like the cells of a closely septaterl hypha, but 

 afterwards become more rounded, increasing considerably in 

 volume and becoming looser, their fairly uniform dimensions 

 then being about 4-5 by 3 ^u, though sometimes as much as 6.1 

 by 4 fji. Individually almost colourless, they give rise to the 

 characteristic shade of the vegetation when closely packed 

 together. The fungus develops abundant sclerotia, differing but 

 slightly in size, form, and tough structure from those of P. glaucum. 



FIG. 1 80. Penicilliuin italicum. 



Conidiophores (i, 2), sterigmata (3, 4), an;l conidia (5). Section through an old 

 Bclerotium (6), the coloured strata of the riud shaded more darkly. Approx. 

 inagn. of 1-2, 400 ; of 3-4, 600 ; of 5, 700 ; of 6, 90. (After Wehmcr.) 



Brefeld. They form small, smooth, brown, fairly uniform, hard, 

 brittle globules, about 300 fj, in diameter, either enveloped in 

 mycelium or bare, and are easily separated at any time by rubbing 

 the vegetative coating between the fingers. Since, up to now, all 

 experiments with a view to the development of ascospores have 

 failed, the sclerotia must, for the time being, be regarded as sterile, 

 in which respect they are on a par with those of Asperyillusfiavus^ 

 A . ochraceus, and A . niger. Nothing definite is yet known as to 

 their life history. The fungus is readily cultivated on the usual 

 mycological substrata, and when grown on sugar solutions con- 

 taining inorganic salts, forms tough, closely matted coatings, 

 colourless below and pale to greyish green above, a large number 



