332 MORPHOLOGY OF THE ASPERGILLACE^E. 



elucidation of this difficult subject may be anticipated from the 

 investigations of THOM (1.), which up to the present have only 

 been outlined. 



It hardly needs emphasising that the form and size of the 

 conidia are constant for one and the same species, and that 

 reports on the transformation of growths with ellipsoidal conidia 

 into such as produce globular conidia as described by GUEGUEN 

 (II.) must be regarded very critically. 



Nothing certain can be stated with regard to the number of 

 species in existence. Undoubtedly a large proportion of the fifty 

 odd alleged species included in SACCARDO'S list (IV.) will have 

 to be deleted, especially since the older descriptions are insufficient 

 for identification. Scarcely one-half of the above number have 

 been clearly characterised, and only a portion of this moiety can 

 be regarded as authentically established. Nearly half the thirty- 

 two species counted by LINDAU (II.) are unrecognisable or 

 doubtful, the old descriptions given by Preuss, Corda, and 

 Bonorden being insufficient as a starting-point, it having been 

 customary at that time to simply describe, without troubling 

 about the previous work of others, in a way that is quite 

 incommensurate with modern requirements. The greatest con- 

 fusion exists at present with reference to the fungus termed 

 lt Penicillium glaucum" of which there appear to be several 

 closely allied species included under this collective name in the 

 literature. In fact we are only on the threshold of real know- 

 ledge in connection with the Penicillium group. A summary 

 of the Penicillium species is given below, theTechnically important 

 members, that have been more accurately described and are dealt 

 with fully later on, being marked with a *. Fuller particulars 

 are set forth by SACCARDO (IV.) and by LINDAU (II.). 



SUMMARY OF PENICILLTUM SPECIES. 



1. Conidial herbage, green : 



P. glaucum * (Link ?) Bref., Sclerotia with subsequent formation of 

 asci ; P. italicum* Wehmer, sterile sclerotia ; P. olivaceum,* 

 Wehmer ; P. luteum, Zukal, soft-skinnned ascospores ; P. rubrum, 

 Stoll ; P. purpurogenum, Stoll ; P. aureum, Corda, soft-skinned 

 ascospores (perithecia) ; P. radiatum, P. Lindner (sclerotia?); 

 P. Wortmanni, Klocker, soft-skinned ascospores (like P. aureum 

 and P. luteum); P. Duclauxii. Delacroix (P. luteum?), P. 

 Camernbert,* ad int. (see also under 4) ; P. Roquefort, ad int. ; 

 P. claviforme, Bain. ; P. granulatum, Bain. 



2. Conidial herbage yellowish to brownish or brown : 

 P. brevicaule,* b'acc. 



3. Conidial herbage reddish to red : 

 P. roseurn, Lk. (?). 



4. Conidial herbage white to light grey : 



P. candidum, Lk., sclerotium with formation of asci ; P. Camembert,* 

 a.i. (herbage temporarily a faint green) ; [P. insignc, (Winter) 

 Schroter, with formation of perithecia ( = Gliocladium peni- 

 cilloides)]. 



