126 A MANUAL OF THE ASPERGILLI 



vation is, in effect, confirmed by George Smith (1931). From textiles in 

 particular he has isolated many small-spored strains but none with large 

 spores. Possibly the present collection contains as many large-spored 

 strains as it does because the authors have regarded them as curiosities, 

 and for that reason retained them, whereas scores of strains of such com- 

 mon species as A . repens or A . amstelodami have been isolated and forthwith 

 discarded. 



In contrast to the small-spored forms, where complete duplication be- 

 tween large numbers of isolates is the rule, among the large-spored forms 

 there is a marked tendency for each strain to present a somewhat different 

 cultural picture, which is commonly coupled with differences in morphology. 

 This would suggest that these forms are unstable and variable, but such a 

 conclusion is refuted by their behavior in culture. To illustrate, culture 

 NRRL No. 131, a strain of Aspergillus echinulatus, has for 20 years of con- 

 tinuous culture by the authors retained its distinguishing characters, simi- 

 larly the single known strain of A. medius has been under observation in 

 this and European laboratories for more than 40 years without appreciable 

 change. 



Thus the problem of assigning a relatively small number of quite distinct 

 strains is presented. To describe each of them would merely add to the 

 confusion already existing, hence they have been grouped somewhat, choos- 

 ing either historic cultures that have become widely distributed or cultures 

 of marked individuality as representing specific names. Homogeneity 

 among the strains brought together is not claimed. The names A. glaucus 

 and E. herbariorum are not identified with particular organisms in this dis- 

 cussion. 



In setting apart a so-called "large-spored series" the authors do not, in 

 any sense, wish to imply close relationship or genetic continuity within this 

 subgroup. Species are grouped together primarily as a matter of con- 

 venience, and (E.) herbariorum is selected as the series designation primarily 

 because of Man gin's usage of this species name to cover all of the large- 

 spored forms. 



Key 



A. Conidial heads green. 



1. Asci ripening within 2 to 4 weeks. 



a. Ascospores 6.5 to 7.5ju in long axis A . mangini n. comb. 



b. Ascospores 7.5 to 8.5ju in long axis A. umbrosus Bain, and Sart. 



c. Ascospores 9.0 to lO.Oju in long axis 



A. echinulatus (Delacr.) Thorn and Church 



2. Asci ripening slowly, 2 to 3 months, colonies favored by 40 per cent sugar. 



a. Ascospores with equatorial ridges and furrow A. medius Meiss. 



b. Ascospores usually without equatorial ridges and furrow 



A. carnoyi (Biourge) Thorn and Raper 



B. Conidial heads white A. niveo-glaucus Thorn and Raper 



