FAMILY CHLA.MYDOBACTERIACEAE 



985 



13.) From Greek ihrix, hair and gcno, 

 producing. 



Long, slender, articulated filaments, 

 free-floating, never branched. Fila- 

 ments 0.5 micron in thickness, composed 

 of rod-like colorless cells. 



Filaments surrounded by a fine sheath. 

 This sheath ruptures longitudinally and 

 rolls up as a fine hair-like body at one 

 side of the filament. This process con- 

 tinually repeated leads to the develop- 

 ment of a thick sheath composed of 

 numerous hair-like bodies arranged in 

 parallel bundles, which are easilj' sepa- 

 rated from the filament. The sheath is 

 completely dissolved in dilute hydro- 

 chloric acid. 



Mode of reproduction is unknown. 



Habitat: Iron-bearing waters. 



3. Leptothrix disccphora (Schwers) 

 Dorff. {Mcgalothrix discophora Schwers, 

 Cent. f. Bakt., II Abt., 33, 1912, 273; 

 Leptothrix crassa Cholodny, Cent. f. 

 Bakt., II Abt., 61, 1924, 292; Chlamydo- 

 thrix discophora Xaumann, Ber. d. 

 Deutsch. Bot. Ges., 46, 1928, 141; Dorff, 

 Die Eisenorganismen, Pflanzenforsch- 

 ung, Heft 16, 1934, 31.) From Latin 

 discus, disk and Greek phorous, to bear. 



Long, slender, articulated filaments 

 composed of elements of varying length 

 showing false branching (Cholodny, loc. 

 cit., 297). L'sually attached to a sub- 

 merged substrate but may be free-float- 

 ing. 



Filaments surrounded by a heavy 

 sheath, thick (10 to 15 microns) at the 

 base, tapering toward the free tip, 

 heavily impregnated with ferric hy- 

 dro .xide. 



Reproduction by motile swarm cells 

 liberated from the tip, and also by the 

 emergence of the filament from the 

 sheath, with subsequent breaking up 

 into individual non-motile cells (co- 

 nidia). 



Habitat : Water. 



4. Leptothrix sideropous (Molisch) 

 Cholodny. {Chlamydolhrix sideropous 



Molisch, Die Eisenbakterien, 1910, 14; 

 Gallionella sideropous Naumann, Kungl. 

 Svenska Vetenskapsakad., 62, 1921, 33; 

 Cholodnj', Die Eisenbakterien, Pflanzen- 

 forschung, Heft 4, 1926, 25.) From 

 Greek sideros, iron. 



Short, unbranched filanients composed 

 of rod-shaped cells of varying length, 

 0.6 m.icron in diameter. 



Sheath very thin^ colorless, giving an 

 iron reaction only at the base of the fila- 

 ment. Attached by a broad holdfast 

 which gives a marked iron reaction. 



Habitat: Found in water, growing on 

 submerged surfaces. 



5. Leptothrix lopholea Dorff. (Die 

 Eisenorganismen, Pflanzenforschung, 

 Heft 16, 1934, 33.) From Greek lophos, 

 crest, tuft. 



Short, slender unbranched filaments, 

 uniform in diameter, attached to a sub- 

 strate, 5 to 13 filaments arising from a 

 common holdfast. Filaments 20 to 33 

 microns long, cells 0.5 by 1.0 to 1.3 

 mic rons . 



Sheaths composed of ferric hj^dro.xide 

 dissolve completely in dilute hydro- 

 chloric acid. 



Filaments creep out of the sheath as in 

 Leptothrix ochracea. 



Habitat: Water. 



6. Leptothrix echinata Beger. (Cent, 

 f. Bakt., II Abt., 92, 1935, 401.) From 

 Latin echinalus, bristled. 



Similar to the preceding species, but 

 occurring in larger colonies, 20 to 50 

 filaments arising from a common hold- 

 fast. Filaments are shorter (9 to 10 

 microns). 



Sheath is thicker at the base and tapers 

 toward the free tip of the filaments, 

 which are slightly spiral. The sheath 

 contains an organic matrix visible after 

 treatment in dilute hydrochloric acid. 



Habitat: Found in water, especially 

 in manganese-bearing waters. 



7. Leptothrix epiphytica (Migula) Ches- 

 ter. (Streptothrix epiphytica Migula, 



