90 A MANUAL OF THE ASPERGILLI 



Key to Groups — Based Primarily Upon Morphology 



The third key is based primarily upon morphology, with colony color 

 employed as an accessory differentiating character. This key is also arti- 

 ficial in construction and is designed to separate the various groups by the 

 simplest and most direct means possible. Groups naturally related may 

 or may not appear in their proper sequence. With the data developed 

 upon the descriptive sheet (p. 82), most of the Aspergilli can be traced 

 to their proper placement in classification schemes by using the following 

 key. Natural arrangement is disregarded and the same group is occasion- 

 ally reached in different places in the key. 



A. Species producing perithecia and ascospores B. 



AA. Species not producing perithecia and ascospores D. 



B. Ascospores colorless C. 



BB. Ascospores purple-red A. nidulans group 



C. Perithecia white to flesh color, enmeshed in a loose net- 



work of colorless hyphae A . fischeri 



CC. Perithecia yellow to orange, naked, vegetative hyphae 



often showing red to orange granules A. glaucus group 



D. Conidial heads cylindrical -clavate; vesicles definitely 



clavate A. clavalus group 



DD. Conidial heads not cylindrical -clavate E. 



E. Colonies showing green or greenish color at some stages 



of development F. 



EE. Colonies lacking green color P- 



F. Conidiophore wall rough or pitted G. 



FF. Conidiophore wall smooth H. 



G. Colonies green or yellow-green to yellowish A . flavus-oryzae group 



GG. Colonies greenish-brown when young, becoming rich 



brown or umber in age A. lamarii group 



H. Sterigmata in one series I- 



HH. Sterigmata in two series K. 



I. Conidia elliptical to pyriform J- 



II. Conidia spinulose, 2.5 to 4 M , globose; chains in com- 



pact columns A. fumigatus group 



J. Colonies mostly showing yellow perithecia; sterigmata 



usually coarse A. glaucus group 



J J. Colonies lacking perithecia; conidia in narrow columns. A. reslrictus group 



