404 



THALLOPHYTES 



Fungi Imperfect! (imperfect Fungi) 



All Fungi in which the features characteristic of the Phycomy- 

 cetes, Ascomycetes, or Basidiomycetes have not been discovered 

 in their life histories are classed as imperfect Fungi. It is a 

 heterogenous group, containing numerous Fungi varying widely 

 in characteristics. Investigators think that most of them are 

 the conidial stages of Ascomycetes in which the Ascogenous 



stage has been abandoned or has not 

 been discovered. Careful investiga- 



4 ^ tions have already discovered that 

 a number of Fungi which have been 

 classed as imperfect Fungi have 

 ascogenous stages and are therefore 

 J||| Ascomycetes. As investigations go 



on no doubt others and probably all 

 of them will be definitely classified in 

 the other groups. 



The spore commonly known in the 

 group is the conidiospore and the 

 character of this spore and the way 

 it is borne are the chief features upon 

 which the group is divided into nu- 

 merous subdivisions. 



% 

 -. 



j 



FIG. 362. Apple affected 

 with Apple Blotch caused by 

 an Imperfect Fungus. From 

 Bulletin 144, Bureau of Plant 

 Industry, U. S. Dept. of 

 Agriculture 



Among them are many disease-producing forms, a large number 

 of which produce serious diseases on cultivated plants. The 

 Early Blight of the Potato, Leaf Blight of Cotton, Black Rot of 

 the Sweet Potato, Fruit Spot of Apples, one of the Potato Scabs, 

 Apple Blotch shown in Figure 362, and numerous other diseases 

 are produced by these Fungi. 



Some special books on Fungi: 



HARSHBERGER, JOHN W. A Text-Book of Mycology and Plant Pathology. 

 STEVENS, F. L. The Fungi which Cause Plant Diseases. 

 DUGGAR, BENJAMIN M. Fungous Diseases of Plants. 

 MASSEE, GEORGE. Diseases of Cultivated Plants. 

 MASSEE, GEORGE AND IVY. Mildews, Rusts, and Smuts. 



