THE GENUS ASPERGILLUS, 321 



285. Aspergillus Species with Branched Sterigmata l 

 (Sectio Sterigrnatoeystis). 



Aspergillus niger, van Tieghem = Sterigmatocystis antacustica> 

 Cramer = Sterigmatocystis niger. This well-known and widely 

 spread species, which has been frequently studied from a chemico- 

 physical standpoint and has a literature of its own, can be identified 

 by the brownish black conidial herbage, with imposing, stiff, 

 slender conidiophores, several millimetres in height. In any 

 event, every Aspergillus of this colour described in the literature 

 under some other name needs careful identification. Specific 

 names, such as A. nigricans, Wreden (1869); A. nigrescens, 

 Robin (1851); and A. nigricans, Cooke, should be abolished 

 entirely ; and at least half a dozen others are in the very doubtful 

 class. The proper specific name pro tern, is Sterigmatocystis 

 anlacustica, which was given by CRAMER (II.) to the fungus he 

 discovered in the passage of the human ear in 1859. As was 

 shown by WILHELM (I.), the fungus afterwards (1867) termed 

 A. niger by van Tieghem coincides with the above species by also 

 possessing branched sterigmata. The morphological examination 

 of the structure of the conidiophores ( Fig. 175), which necessitates 

 the removal or bleaching of the dark masses of conidia, reveals a 

 pale, rigid stem, about 15 p thick, carrying a sharply defined 

 spherical globule (diameter about 80 /*), with slender radial 

 primary sterigmata (26 ^ by 4.5 /j.) each with 3-4 ornamental 

 secondaries (8 by 3 ju), and long chains of small globular, smooth 

 or warty conidia (about 3-4 /j) as carriers of the dark colour. 

 Moreover, the reports of various authorities do not altogether 

 agree, the dimensions of the conidia being oftentimes given as 

 3.4-4.5 yw, and the length of the sterigmata as 20-100 p. This 

 must be specially emphasised, in view of the diagnosis of the black 

 species, to be described later. Of course the heads vary in size, 

 and the result obtained depends on which of them have been 

 measured, unless the average betaken. In unfavourable circum- 

 stances, for instance, unsuitable media, the conidiophores languish 

 (few sterigmata and simple, conidia pale, &c.), as was observed by 

 DUCLAUX (XX.), and more recently by MOLLIARD and COUPIN (I.), 

 as well as by LUTZ (II.). C. ENGELKE (I.) states that, under 

 certain conditions, a conidial form, similar to that of Bolrytis, 

 Sctptromyces Opizii, Corda, is produced ; but this somewhat 

 improbable report requires confirmation on the basis of indubit- 

 ably pure cultures. 



Sclerotia have been frequently observed in this fungus, the 

 first to discover them being K. WILHELM (I.) in 1877; but 

 unaccompanied by any development of asci. According to 



i The division is by no means sharp, some species exhibiting both simple 

 and branched sterigmata. 



