3 oo MORPHOLOGY OF THE ASPERGILLACE^E. 



barely 20 fully described. The conidial herbage is green, yellow, 

 reddish brown, blackish brown or white. 



The genus Penicillium, Link, produces conidiophores, which are 

 delicate, barely distinguishable from the ordinary hyphse, always 

 less than i mm. in height, with septate stalk, polycellular, 

 branched alternately or in whorls near the apex, and without 

 terminal swelling. The conidial chains are produced on simple 

 successive sterigmata which, in most cases, form tufts on the 

 ends of the branches. The conidiophores, where such are known 

 to exist, resemble those of AspergiUus, being delicate or tough, 

 with or without a cortical envelope, developing continuously or 

 intermittently, or remaining sterile for a time according to the 

 species, and are usually formed by the fusion of two similar 

 hyphse (P. glaucum, Brefeld). The number of species is still 

 uncertain, about 100 having been set up, but only about 

 12 properly described. The conidia form a herbage, generally 

 green in colour, more rarely white, red, brownish yellow or 

 brown. 



The genus Citromyces, Wehmer, has delicate conidiophores, 

 like those of Penidllium, but unbranched, carrying a tuft of 

 sterigmata with more or less developed terminal swelling, sparsely 

 septated or not at all. The chains of conidia are invariably 

 arranged as projections formed in succession on the swelling or 

 apex of the stalk of the sterigmata, which may be single, tufted 

 or whorled. The herbage is green. Asci are unknown. Two 

 species have been more fully investigated. 



The genus Allescheria, Saccardo and Sydow ( = Eurotiopsis, 

 Costantin), has sympodial branched conidiophores, from which 

 chains of oval conidia are formed by constriction, which differ 

 appreciably in other respects from those of the foregoing genera. 

 The carpoasci are globular (perithecia), and the asci contain 8 

 spores. The herbage is white to reddish or red. Up to now 

 only a single (rare) species is known. 



283. The Genus Asperglllus. 



In this genus we include all the mould fungi possessing the 

 characteristic AspergUlus conidiophore (with globular terminal 

 swelling developing sterigmata), and do not set Steriymatocystis 

 (with branched sterigmata) or Eurotium (forming perithecia) 

 apart as separate genera. 



The genus, characterised by the shape of the conidiophores, 

 comprises a considerable number of species that are not always 

 easily differentiated, and for whose identification the morpho- 

 logical details of that organ are of importance. In fact 

 these details alone are sufficient to characterise the species in 

 many cases ; and this is the point with which we are now con- 

 cerned, not with the investigation of the obscure conditions of 



