FAMILY I. CHLAMYDOBACTERIACEAE 



267 



and heavily impregnated with iron oxide, 

 surrounds the trichomes. Reproduction by 

 motile swarm cells liberated from the tip 

 and also by the emergence of the trichome 

 from the sheath, with subsequent breaking 

 up into individual, non-motile cells. Not 

 acid-fast. Gram-negative. 



Gelatin not liquefied. 



Iron citrate and ammonium agar colonies: 

 More or less rounded, with oily inclusions, 

 filamentous border. 



Manganese acetate agar colonies: Fila- 

 mentous growth, the filaments being rather 

 large and showing false branching. 



Iron citrate and ammonium agar slant: 

 Growth only in the water of condensation, 

 rarely on the slant. 



Peptone and manganese acetate broth: 

 Abundant growth in the form of loose flakes. 



Indole not produced. 



Hydrogen sulfide not produced. 



Acetylmethylcarbinol not produced. 



Nitrites produced from nitrates. 



Optimum temperature, between 25° and 

 28° C. 



Optimum pH, 8.5. 



Aerobic; growth not favored by the pres- 

 ence of CO2 . 



Habitat : Found in fresh water; widely dis- 

 tributed. 



5. Leptothrix major Dorff, 1934. (Dorff 

 Die Eisenorganismen, Pflanzenforschung, 

 Heft 16, 1934, 35; also see Beger and Bring- 

 mann,Zent. f.Bakt., IIAbt., 107, 1953,323.) 



ma'jor. L. comp.adj. major larger. 



Trichomes, up to 1 and more cm in length, 

 attached by a holdfast, richly branched, 

 forming tufts. Trichomes composed of rod- 

 like cells, 1.4 by 5 to 10 microns, which con- 

 tain small false vacuoles. Giant cells up to 

 75 microns in length. Two trichomes may be 

 found in the same sheath. The sheath may 

 be as much as 12 microns in thickness, taper- 

 ing to the tip, storing manganese and iron. 

 Resembles the sheath of Leptothrix disco- 

 phora but is firmer in texture. Light to dark 

 l)rown in color. 



Source: From the Spree River near Berlin. 



Habitat: Found in fresh- water streams. 



6. Leptothrix lopholea Dorff, 1934. (Die 

 Eisenorganismen, Pflanzenforschung, Heft 

 16, 1934, 33.) 



lo.pho'le.a. Gr. noun lophus a crest; 

 M.L. dim. adj. lopholeus somewhat crested 

 or tufted. 



Short, slender unbranched trichomes, 

 uniform in diameter, attached to a sub- 

 strate, 5 to 13 trichomes arising from a 

 common holdfast. Trichomes 20 to 33 mi- 

 crons long, cells 0.5 by 1.0 to 1.3 microns. 



Sheaths composed of iron oxide; dissolve 

 completely in dilute hydrochloric acid. 



Trichomes slip out of the sheath as in 

 Leptothrix: ochracea. 



Habitat: Water. 



7. Leptothrix echinata Beger, 1935. 

 (Zent. f. Bakt., II Abt., 92, 1935, 401.) 



e.chi.na'ta. Gr. noun echinus the hedge- 

 hog; M.L. adj. echinatus like the hedgehog, 

 bristly. 



Similar to the preceding species but oc- 

 curring in larger colonies, 20 to 50 trichomes 

 arising from a common holdfast. Trichomes 

 are shorter (9 to 10 microns). 



Sheath is thicker at the base and tapers 

 toward the free tip of the trichome, which is 

 slightly spiral. The sheath contains an or- 

 ganic matrix visible after treatment in di- 

 lute hydrochloric acid. 



Habitat: Found in water, especially in 

 manganese-bearing waters. 



8. Leptothrix epiphylica (Migula, 1895) 

 Schoenichen and Kalberlah, 1900. (Strepto- 

 thrix epiphytica Migula, in Engler and 

 Prantl, Die natiirl. Pflanzenfam., /, la, 

 1895, 36 and 38; Chlamydothrix epiphytica 

 Migula, Syst. d. Bakt., 2, 1900, 1033; Schoe- 

 nichen and Kalberlah, Eyferth's Einfachste 

 Lebensformen, 3rd ed., 1900, 46.) 



e.pi.phy'ti.ca. Gr. prep, epi' upon; Gr. 

 noun phytum plant; M.L. adj. epiphyticns 

 epiphytic, growing on plants. 



Chains of cells enclosed in short, colorless 

 trichomes which are surrounded by thick, 

 gelatinous masses; the gelatinous masses are 

 attached to algae, but never in groups or 

 clusters. 



Habitat: Widely distributed in fresh 

 water containing algae. 



