1022 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



of Sorangium compositum, by Krzemien- 

 iewski, Acta Soc. Bot. Poloniae, 5, 

 1927, 96.) 



Etymology : Named for Julius Schroeter 

 (1837-1894). 



Swarm stage (pseudo Plasmodium) : Not 

 described. 



Fruiting bodies: Very small, circular, 

 swollen, often kidney -shaped with brain- 

 like convolutions, usually 60 microns 

 (occasionally 120 microns) in diameter, 

 bright orange-red. Surrounded by a 

 delicate slime membrane about 0.7 micron 

 thick, apparent only with high magnifica- 

 tions. Divided secondarily into angular 

 cysts, by sutures extending inward which 

 divide the mass regularly into well 

 delimited portions, many angled, usually 

 about 12 microns in diameter, and in other 

 places into areas less well delimited and 

 about 14 microns in diameter. Re- 

 sembles gelatin which has dried in a 

 sheet and cracked into regular areas. 

 Rods in cysts 5 microns long. Cysts 

 sometimes occur together in large num- 

 bers, covering an area to 0.5 mm. 



Source and habitat : Found by Jahn 

 {loc. cit.) five times on rabbit dung in 

 environs of Berlin. 



Illustrations: Jahn (1924, loc. cit.), 

 PI. 2, Fig. 22. 



2. Sorangium sorediatum (Thaxter) 

 Jahn. {Polyangium sorediatum Thaxter, 

 Bot. Gaz., 37, 1904, 414; Jahn, Beitrage 

 zur botanischen Protistologie. I. Die 

 Polyangiden, Geb. Borntraeger, Leipzig, 

 1924, 73.) 



Etymology: From Greek, soros, heap, 

 probably through the botanical term 

 soredium, one type of reproductive body 

 in the lichen, and sorediate, with surface 

 patches like soredia. 



Swarm stage (pseudoplasmodium) : 

 Rods 0.8 by 3 to 5 microns. Attempts to 

 cultivate have failed. 



Fruiting body : Orange-red, irregularly 

 lobed, consisting of a compact mass of 

 small angular cysts. Average size of 

 cysts 6 to 7 microns, smallest 3 microns, 



with thick and sharply defined edges. 

 Rods 0.8 by 3 to 5 microns. The Krze- 

 mieniewskis (1927, loc. cit., 96) have 

 described a variety, Sorangium sore- 

 diatum var. macrocystum, consisting of 

 cysts 6 to 14 by 7 to 16 microns, about 

 twice as large as in the type. 



Source and habitat : Reported once by 

 Thaxter (loc. cit.) on rabbit dung from 

 South Carolina. Krzemieniewski (1927, 

 loc. cit.) common in Polish soils. 



Illustrations: Thaxter (loc. cit.) PI. 

 27, Figs. 22-24. Quehl, Cent. f. Bakt., 

 II Abt., 16, 1906, 9, PI. 1, Fig. 2. Jahn, 

 Kryptogamen-flora d. Mark Branden- 

 burg, V, Pilze I, Lief. 2, 1911, 202, Fig. 1. 

 Krzemieniewski, Acta Soc. Bot. Pol., 4, 

 1926, PI. IV, Figs. 39-41. (1927, loc. 

 cit.) PI. V, Fig. 17, var. macrocystum 

 Fig. 18. 



3. Sorangium cellulosvim Imsenecki 

 and Solntzeva. (Microbiology, Moscow, 

 6, 1937, 7.) 



Etymology : Modern Latin cellulosum, 

 cellulose. 



Fruiting body : Mature fruiting body 

 rusty brown, 400 to 500 microns in 

 diameter, sessile on layer of partially 

 dried slime. No outer wall or limiting 

 membrane. Composed of numerous 

 cysts, irregular in shape, 1.6 to 3.2 

 microns in diameter, each containing 

 less than ten shortened rods. No dis- 

 cernable cj^st wall or membrane. 



Spores: 0.3 by 1.5 to 2.0 microns (no 

 other data). 



Vegetative cells : Flexible, rod-shaped 

 cells with rounded ends, occurring singly ; 

 no flagella but motile by means of a 

 crawling motion; 0.4 to 0.6 by 2.2 to 4.5 

 microns. 



Vegetative colonj^ : No data. 



Physiology: Good growth on starch, 

 cellulose. Decompose up to 24 per cent 

 cellulose in ten days, but does not form 

 fruiting bodies. Very poor growth on 

 arabinose with formation of many involu- 

 tion forms including very much elongated 



