FAMILY III. SORANGIACEAE 



869 



ondary cysts 10 to 12 microns. The Krzemie- 

 niewskis (Acta Soc. Bot. Poloniae, 5, 1927, 

 96) recognize a variety, Sorangium septatum 

 var. microcystum, which has secondary cysts 

 with dimensions 3 to 8 by 4 to 10 microns. 



Source: Collected twice from horse dung 

 in Cambridge, Mass. 



Habitat: Found on decaying organic mat- 

 ter in soil and in the dung of various ani- 

 mals. Reported by Krzemieniewski {loc. 

 cit.) as common in Polish soil. 



Illustrations: Thaxter (op. cit., 1904, PI. 

 27, Figs. 25-28), Jahn (Kryptogamen-flora 

 d. Mark Brandenburg, V, Pilze I. Lief 2, 

 1911, 202, Fig. 2) and Krzemieniewski (Acta 

 Soc. Bot. Poloniae, 4, 1926, PI. 27, Figs. 27- 

 38; also see ihid., 1927, PI. V, Fig. 15, var. 

 microcystum, Fig. 16). 



6. Sorangium coniposituni (Thaxter, 

 1904) Jahn, 1924. {Polyangium compositiim 

 Thaxter, Bot. Gaz., 37, 1904, 413; Jahn, 

 Beitriige zur bot. Protistologie. I, Die Poly- 

 angiden. Geb. Borntraeger, Leipzig, 1924, 

 74; Polyangium sorediatum Quehl, Cent. f. 

 Bakt., II Abt., 16, 1906, 17; not Polyangium 

 sorediatum Thaxter, op. cit., 1904, 414.) 



com.pos'i.tum. L. adj. compositus com- 

 pound. 



Vegetative cells: Not described. 



Fruiting bodies: Dull yellowish orange 

 changing to dark red on drying. Rounded, 

 small, 0.5 to 1 mm, usually as a whole or 

 even in larger clumps surrounded by a deli- 

 cate and evanescent membrane. In large 

 fruiting bodies the cysts are bound together 

 in balls, 70 to 90 microns in diameter, by a 

 delicate membrane. The balls readily fall 

 apart. Secondary cysts are angular, 7 by 11 

 microns, surrounded by a delicate orange- 

 red membrane about 0.4 micron in thick- 

 ness. Length of rods in the cysts, 5 microns. 



Source : Found on rabbit dung from South 

 Carolina. Jahn (op. cit., 1904) found it four 

 times on rabbit dung near Berlin, twice on 

 hare dung in Oberharg. 



Habitat: Found on decajang organic mat- 

 ter in soil and in the dung of various ani- 

 mals. Common in soils of Poland according 

 to Krzemieniewski (Acta Soc. Bot. Pol- 

 oniae, 5, 1927). 



Illustrations: Thaxter (op. cit., 1904, PI. 

 27, Figs. 29-30), Jahn {pp. cit., 1924, PI. I, 



Fig. 6) and Krzemieniewski {op. cit., 4, 

 1926, PI. Ill, Figs. 32-36; ibid., 5, 1927, PI. 

 IV, Figs. 7-12; PI. V, P^igs. 13-14; PI. VI, 

 Fig. 36). 



7. Sorangium nigrum Krzemieniewska 

 and Krzemieniewski, 1937. (Bull. Int. 

 I'Acad. Pol. Sci. et Lettres, Classe Sci. 

 Math, et Nat., Ser. B, 15, 1937.) 



ni'grum. L. adj. niger black. 



Vegetative cells: 1.1 to 1.3 by 2.5 to 5.5 

 microns. 



Fruiting body: Primary cysts generally 

 not formed; when observed, appeared as 

 smoke-colored slime envelope surrounding 

 clumps of a few cysts. Secondary cysts usu- 

 ally arranged in rows within cellulose fibers, 

 the material of the fiber forming a common 

 sheath. Each individual cyst is enclosed by 

 a cyst wall, clearly differentiated from the 

 tubular-shaped cellulose fibers. Cysts meas- 

 ure 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. 



Colonies: Young colonies are black in 

 color. On filter paper a bright orange margin 

 is noted, the vegetative 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 com- 

 pact accumulation of cysts and cellulose 

 fibers. 



Physiology: Cellulose fibers become swol- 

 len by the action of this organism and be- 

 come 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. 



Illustrations: Krzemieniewskis {ibid., 

 Plate IV, Figs. 22-26). 



8. Sorangium nigrescens Krzemie- 

 niewska and Krzemieniewski, 1937. (Bull. 

 Int. I'Acad. Pol. Sci. et Lettres, Classe Sci. 

 Math, et Nat., Ser. B, 15, 1937.) 



ni.gres'cens. L. part. adj. nigrescens be- 

 coming black. 



Vegetative cells: 1.2 to 1.4 by 2.5 to 6.4 

 microns. Younger cells somewhat shorter. 



