CLASS SCHIZOMYCETES NAGELI 



(Bericht Verhandl. d. bot. Section d. 33 Versammling deutsch. Naturforsch. u. 

 Arzt. Bot. Ztg., 1857, 760.) 



Synonyms: Bacteria Cohn, Beitr. Biol. d. Pflanzen, 1, Heft 1, 1872, 136; Bacteria- 

 ceae Cohn, ibid., 237; Bacteriales Clements (as an ordinal name), The Genera of Fungi, 

 Minneapolis, 1909, 8; Schizomycetaceae De loni and Trevisan, in Saccardo, Sylloge 

 Fungorum, 8, 1889, 923; Schizomycetacea Castellani and Chalmers, Manual of Trop- 

 ical Medicine, 3rd ed., 1919, 924; Mychota Enderlein, Eakteriencyclogenie, 1924, 236 

 Schizomycetae Stanier and Van Niel, Jour. Bact., 42, 1941, 458. 



Typically unicellular plants. Cells usually small, sometimes ultramicroscopic 

 Frequently motile. As in the closely related blue-green algae (Class Schizophyceae) 

 the cells lack the definitely organized nucleus found in the cells of higher plants and 

 animals. However, bodies containing chromatin which may represent simple nuclei 

 are demonstrable in some cases. Individual cells may be spherical; or straight 

 curved or spiral rods. These cells may occur in regular or irregular masses or even 

 in cysts. Where they remain attached to each other after cell division, they may 

 form chains or even definite filaments. The latter may show some differentiation 

 into holdfast cells, and into motile or non-motile reproductive cells (conidia). Some 

 grow as branching mycelial threads whose diameter is not greater than that of ordi- 

 nary bacterial cells, i.e., about one micron. Some species produce pigments. The 

 true purple and green bacteria possess pigments much like or related to the true 

 chlorophylls of higher plants. These pigments have photosynthetic properties. 

 The phycocyanin found in the blue green algae does not occur in the Schizomyceies. 

 Multiplication is typically by cell division. Endospores are formed by some species 

 included in Eubacteriales. Sporocysts are found in Myxobacteriales. Ultramicro- 

 scopic reproductive bodies are found in Borrelomycetaceae. The bacteria are free- 

 living, saprophytic, parasitic or even pathogenic. The latter types cause diseases 

 of either plants or animals. Seven orders are recognized. 



Key to the Orders and Sub-Orders of the Class Schizomycetes. 



A. Cells rigid, not flexuous. Motility by means of flagella or by a gliding movement. 

 1. Cells single, in chains or masses. Not branching and mycelial in character. 

 Not arranged in filaments. Not acid-fast. Motility when present by means of 

 flagella. 



Order I. Eubacteriales, p. 66. 

 a. Do not possess photosynthetic pigments. Cells do not contain free sulfur, 

 b. Not attached by a stalk. Do not deposit ferric hydroxide. 



Sub-Order I. Eubacteriineae, p. 67. 

 bb. Attached to substrate, usually by a stalk. Some deposit ferric hy- 

 » droxide. 



Sub-Order II. Caulobacteriineae, p. 827. 

 aa. Possesses photosynthetic chlorophyll -like pigments. Some cells contain 

 free sulfur. 



Sub-Order III. Rhodobacteriineae, p. 838. 



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