280 PART IV. CLASSIFICATION. 



remarkable polymorphism especially in the higher forms which 

 pass through several distinct phases in the course of their life. 

 Again, in some Ascomycetes and ^Ecidiomycetes there may be two 

 or three forms bearing different kinds of reproductive organs, the 

 different forms being parasitic on different hosts (hctercecisiri). 

 The Fungi may be classified as follows : 



Sub-Class I. SCHIZOMYCETES : Body unicellular, or multi- 

 cellular and filamentous ; no special spore- 

 bearing organs ; no sexual reproduction. 



Sub-Class II. MYXOMYCETES : Body a plasmodium ; spores 

 formed in more or less well-developed spor- 

 angia ; zoospores ; no sexual reproduction. 



Sub-Class III. PHYCOMYCETES : Body generally a coenocytic 

 unseptate mycelium ; sexual reproduction 

 general ; zoospores present in most orders. 



Section A. Zygomycetes: sexual process 

 isogamous ; product, a zygospore. 



Section B. Oomycetes : sexual process 

 oogamous ; product, an oospore. 



Sub-Class IV. ASCOMYCETES : Body usually an incompletely 

 septate mycelium; sexual process carpoga- 

 mous ; the product is an ascocarp. 



Sub-Class V. JEciDiOMYCETES : Body an incompletely septate 

 mycelium ; no sexual process. 



Sub-Class VI. BASIDIOMYCETES : Body an incompletely septate 

 mycelium; no sexual process; compound 

 sporophores are always formed. 



Sub-Class I. SCHIZOMYCETES. These organisms are either uni- 

 cellular or multicellular ; most of the unicellular forms are very 

 minute. The cell consists of a mass of protoplasm, with a rudimen- 

 tary nucleus, surrounded by a cell- wall which consists in some cases 

 of cellulose, and in others of a proteid substance. In some cases 

 the cells are coloured red, green, blue, etc. ' a starchy substance, 

 turning blue with iodine, is found in the cells of some forms 

 (e.g. Bacillus Amylobacter). 



The forms presented are extremely various. The individuals 

 may be spherical, the Coccus-form (Fig. 162, a) ; or rod-shaped, the 

 Bacterium-form (Fig. 162, &) ; or spirally-wound, the Spirillum- 

 and Spirochsete-forms (Fig. 162, d) ; or straight free filaments, the 

 Bacillus-form ; or straight filaments attached by one end, the Cre- 



