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MANUAL OF DETERMINATIVE BACTERIOLOGY 



Illustrations : Thaxter (loc. cit.) PI. 27, 

 Figs. 29-30. Jahn (1924, loc. cit.) PI. I, 

 Fig. 6. Krzeniieiiiewski, Acta Soc. Bot. 

 Pol., 4, 1926, PI. Ill, Figs. 32-36; ibid., 

 1927, 5, PI. IV, Figs. 7, 8, 9, 10, 11, 12; 

 PI. V, Figs. 13, 14; PI. VI, Fig. 36. 



7. Sorangium nigrvim Krzemieniewski. 

 (Bull. Int. I'Acad. Pol. Sci. et Lettres, 

 Classe Sci. Math, et Nat., Ser. B, 15, 

 1937.) 



Etymology : Latin niger, black. 



Fruiting body : Primary cysts generally 

 not formed; when observed, appeared as 

 smoke-colored slime envelope surround- 

 ing clumps of a few cysts. Secondary 

 cysts usually arranged in rows within 

 cellulose fibers, the material of the fiber 

 forming a common sheath. Each indi- 

 vidual cyst inclosed by a cyst wall, 

 clearly differentiated from the tubular- 

 shaped cellulose fibers. Cysts measure 

 9 to 16 by 9 to 23 microns; average 10 by 

 18 microns. Cyst wall moderately thick, 

 colorless, transparent, becoming light 

 brown with age, and finally black. 



Spores : No data. 



Vegetative cells: 1.1 to 1.3 by 2.5 to 

 5.5 microns. 



Vegetative colony : Young colonies 

 dead black in color. On filter paper a 

 bright orange margin is noted, the vegeta- 

 tive cells of which cover the cellulose 

 fibers. On cotton cloth the margin is 

 bright dirty-yellow, tinged with pink. 

 Under low power magnification, center of 

 the colony appears similar to matted 

 fungal hyphae, due to characteristic 

 compact accumulation of cysts and cel- 

 lulose fibers. 



Physiology : Cellulose fibers become 

 swollen by the action of this organism, 

 and become gray-brown with a violet 

 tinge. Fibers lose the properties of 

 cellulose and give no characteristic 

 reactions. 



Source : Isolated from soil. 



Habitat: Soil. Decomposes cellulose 

 fibers. 



Illustrations : Krzemieniewski (loc. 

 cit.) Plate IV, Figs. 22-26. 



8. Sorangium nigrescens Krzemie- 

 niewski. (Bull. Int. I'Acad. Pol. Sci. 

 et Lettres, Classe Sci.. Math, et Nat., 

 Ser. B, 15, 1937.) 



Etymology : Latin nigrescens, becoming 

 dark or black. 



Fruiting body : Primary cysts vary in 

 size up to 200 microns in diameter, 

 irregular in shape and inclosed in a 

 colorless slime envelope. Formed by an 

 accumulation of secondary cysts. Sec- 

 ondary cysts at first colorless, transparent , 

 later becoming brownish with a limiting 

 membrane; the young cysts appear 

 dirty-yellow, the older ones grayish- 

 brown to black. Color originates not 

 only from the brownish cyst wall but 

 from the gray mass of encysted cells. 

 Secondary cysts measure 5 to 12 by 6 to 

 15 microns ; average 6 by 10 microns. On 

 filter paper not only well -formed primary 

 cysts are formed, but also free secondary 

 cysts are noted embedded in the slime 

 of the colony. 



Spores :No data. 



Vegetative cells : 1.2 to 1.4 by 2.5 to 6.4 

 microns. Younger cells somewhat 

 shorter. 



Vegetative colony : Mass of dark fruit- 

 ing bodies develops at center of colony on 

 filter paper; margin grayish-yellow. Cel- 

 lulose fibers covered with vegetative 

 cells on outside, and contain many cells 

 within. 



Physiology: Destroys cellulose. Culti- 

 vated six years with cellulose as carbon 

 source. 



Source: Isolated from sandy soil in 

 pine woods in Ciemianka (?). 



Habitat: Soil. Decomposes cellulose 

 fibers. 



Illustrations : Krzemieniewski {loc. 

 cit.) Plate III, Figs. 17-21. 



