The Fungi— Molds 359 



KINGDOM: Plant 



PHYLUM: ThaUophytes (Lack roots, stems, and leaves) 



I. Eumycetes (True fungi) 



CLASS: 1. Phy corny cetes (Algae-like fungi) 

 GENUS: A. Rhizoptis 

 B. Mucor 



2. Ascomycetes (Sac fungi) 



A. Aspergillus 



B. Penicillium 



3. Basidiomy cetes (Club fungi) 



Includes puffballs, mushrooms, toadstools, smuts, and 

 rusts. 



4. Fungi Imperfecti (Heterogeneous group in which 

 sexual reproduction has not been demonstrated) 

 Includes certain mildews, plant pathogens, and food 

 spoilage fungi, and it may also include organisms 

 given the same generic names as in other classes, just 

 as if they had sexual reproductive methods. Ex. 

 Aspergillus species (Fungi Imperfecti). The Geo- 

 trichum genus is classified as a member of the Fungi 

 Imperfecti. 



II. Psetidomycetes (False fungi) 

 CLASS: Myxomycetes (Slime molds) 



Molds resembling protozoa. 



MORPHOLOGY 



Molds are identified and classified largely on the basis of mor- 

 phology, with physiological reactions assuming secondary impor- 

 tance. The cell walls on fungi are thick and rigid and are com- 

 posed principally of chitin (the horny-like substance found on 

 insects). Just as is true with bacterial cells, molds have a cyto- 

 plasmic membrane which limits the cytoplasm within the cell. As 

 the plant matures, vacuoles form within the cells, and these vacu- 

 oles consist of glycogen (a sugar related to starch and dextrin), 

 fat, and volutin ( chiefly a chemical called ribonucleic acid ) . 



Molds develop into thread-like structures termed hyphae (sin- 

 gular hypha), and a mass of hyphae is called a mycelium. Micro- 

 scopic examination of these threads will reveal that some of them 

 are sectioned into individual cells by means of cross walls, or septa 



