THE GENUS ASPERGILLUS. 305 



of consideration at present, unless weighty practical considerations 

 be sacrificed to purely scientific points. 



The following summary relates to species of Aspergillus which 

 form perithecia or sclerotia : 



A. PERITHECIA (with immediate formation of asci). 



A. ctea ( Pel ' UheCiUm '"> M Without 



wlth^ell. 



B. SCLEROTIA (asci formed after a while, or still unknown). 



1. A. nidulans, with retarded formation of asci, and shell. 



2. A. ochraceus^ 



3. A. niger 



4. A. flai'US J 



I Asci not yet observed. With or without simple 

 mycelial sheath. 



Eidam applied the name perithecium also to the tough-skinned 

 organs of A. nidulans, which develops asci gradually, but also 

 emphasises their intermediate position between the Eurotium 

 capsules and the sclerotia. 



Undoubtedly a large number of species will have to be struck 

 out of the present list of about 120, the diagnosis made by older 

 workers having been in many cases insufficient for the establish- 

 ment of a new species. Their general practice was merely to 

 describe and not compare, the latter having been difficult, owing 

 to the scattered literature, previous to the appearance of Saccardo's 

 SyllogcK. Probably not more than two or three dozen are really 

 admissible, a circumstance that unfortunately has not been duly 

 considered by modern German workers, LINDAU (I.), for instance, 

 mentioning no less than 55 species, of which only 17 are classed 

 as doubtful ; and only a small fraction of these have any interest 

 for the technical mycologist. Nevertheless this genus is more 

 important than the majority, since it comprises not only several 

 species that find industrial application (A. oryzce, A. Wentii, A. 

 luchuensis), but also others noteworthy on account of chemico- 

 physiological considerations (A. niger) and several which are patho- 

 genic toward men and animals (A.fumigatus, A.flavus, A. nidu- 

 lans), whilst others again (A. glaucus, A. phcenicis, A. davatus, A. 

 fumigatus) are occasionally found in industrial processes, com- 

 mercial products, food-stuffs, &c. Whether certain species are 

 directly pathogenic toward plants may be left out of consideration, 

 though, according to PAMMEL, WEEMS, and LAWSON-SCRIBNER (I.), 

 A. glaucus and others are the cause of disease in embryo grasses. 

 On the other hand, J. BEHRENS (XVI.) found A. glaucus 

 ( = A.medius, Meissner) harmless, but A. niger dangerous. At all 

 events, the genus Aspergillus forms the most interesting, because 

 the most diversified, genus of fungi, except for the Saccharomycetes. 



