EU-MYCETES.-(a) ASCOMYCETKS 433 



commonest are readily distinguished by tiieir stature an<I colour 

 Low-growmg, velvety, blue-green patches are Penicillium cmstaceum ' 

 coarser, olive-green patches, with mop-like heads, of size ^ ' 

 to the naked eye, are Aspergillus (Emotium) herbariorum \ 

 patches of the latter grow older, minute yellow specks may app<^ar 

 upon them : these are the Eurotium-ixmts, a stage originally dcs. - ^ ' 

 as a distinct fungus. A breath will carry away the numerous c 

 from such a culture in a dense cloud. They form part of the ordmar>- 

 dust of dwelhngs, and this accounts for the constant appf------ r'f 



Fig. 366. 



Conidiophores of Aspergillus herbariorum (to the left) and of Penicillium cruttatmm 

 ' (to the right.) (From Strasburger.) Highly magnified. 



the Moulds on organic substrata where the conditions are favourable 

 to their growth, as in the moist air in a close cupboard or unricr a 

 bell-jar. 



If a sample of Aspergillus be taken, the branched and .septate 

 mycehum is seen to ramify over and penetrate into the organic 

 substratum, deriving nourishment till able to propagate. Stout 

 branches then rise upright as conidiophores, which swell upwards 

 into a spherical head. On this numerous conical sterii^miUa l)ud 

 forth, each giving rise to a chain of conidia, formed in basipelal 

 succession. The oldest is distal, and successively others are abstricted 

 off : an arrangement which provides for the due nourishment of each, 

 and the ready removal of those that are mature by any breath of air ; 

 for these minute polynucleate bodies are very lightly attached 

 (Fig. 366). They germinate readily in water or damp air, and the 



13. B. 2 K 



