SACCARDO'S CLASSIFICATION 97 



The remaining Moniliales are grouped into two families according 

 to the color of the mycelium. If this is hyaline or brightly colored, 

 the mold is included in the Moniliaceae (Mucidinaceae) ; if it is 

 dark, smoky (black or shades of deep grey, brown, or olive), the 

 mold belongs to the Dematiaceae. This is not a good character for 

 such an important division. Many genera vary considerably in this 

 character and frequently hyaline variants (saltants) are produced 

 in some cultures of the Dematiaceae. These if isolated in nature 

 would be included in a different family from their parent! 



Perhaps it is fortunate that the Fungi Imperfecti have not been 

 accorded the continual reclassification to which mycologists have 

 (for very good reason) subjected the perfect fungi. Since a natural 

 system at our present stage of knowledge can hardly be attained, any 

 classification has been one for convenience only and such reclassifica- 

 tions as have been proposed are not very great improvements upon 

 the original Saccardo system. The imperfect yeasts and yeast-like 

 fungi are put into four additional families of the Monihales. See 



page 285. 



A very large number of genera and species of the Moniliales have 

 been described. A very large proportion of these are rare, many of 

 them of doubtful validity. To present a complete key would defeat 

 the purpose of this book. But experience shows that the molds likely 

 to be encountered by the bacteriologist will fall within a few genera ; 

 fully three-fourths of those encountered in routine work will be 

 species of Aspergillus and Penicillium. We shall, therefore, describe 

 very briefly only a few genera and indicate where further informa- 

 tion may be obtained. 



The key to the molds belonging to the Fungi Imperfecti published 

 by Lindau in Rabenhorst's Kryptogamenflora has been followed by 

 most mycologists. It has been published in translation in Waksman's 

 Principles of Soil Microbiologij ^^ and in Buchanan's Bacteriology.^ 

 Very complete keys with descriptions of species found in soil will be 

 found in Oilman's Manual of Soil Fungi} Soil forms are naturally 

 likely to appear as laboratory contaminants. 



The fungi parasitic to man and animals will offer special difficul- 

 ties. A very excellent Manual of Clinical Mycology by Conant * 

 and associates gives descriptions and illustrations of the most com- 

 mon and important species. INIany other forms will be found in 

 Lewis and Hopper's Introduction to Medical Mycology.^" The older 

 books of Castellani and Sartory are no longer of much value. A 

 very large, fairly recent book of Dodge ^ may also be consulted. 

 Jlowever, the inclusion in it of a large number of species for which 



