FAMILY IV. POLYANGIACEAE 



873 



sometimes seen within the C3\st. When 

 treated with H2SO4 , cysts are easily broken 

 up under the cover glass. Fruiting bodies 

 are composed of climips of cysts. The fruit- 

 ing bodies are ellipsoidal or pear-shaped, 

 40 to 55 by 110 to 160 microns, reddish 

 brown; they are covered with a slime mem- 

 brane (flakes of dried slime). Each is com- 

 posed of 12 to 40 cysts which become poly- 

 gonal from pressure. The cysts are some- 

 times arranged in chains. 



Resting cells: 0.7 to 0.8 by 2.2 to 3.5 mi- 

 crons. 



Vegetative colony: Cysts germinate on 

 filter paper producing vegetative colonies. 

 Colonies large, orange, moist, increasing in 

 size. The older colonies have orange margins 

 while the center is dark brown, correspond- 

 ing to the color of the fruiting bodies. Often 

 show several concentric rings. 



Physiology: Rods cover cellulose fibers, 

 partially or completelj^ destroying them. 

 Paper becomes transparent. 



Optimum temperature, between 18° and 

 22° C. Very slow growth at 30° C. 



Grows only on cellulose, not in ordinary 

 media. 



Aerobic. 



Source: Isolated from soil. 



Illustrations: Imsenecki and Solntzeva 

 {ibid., Table II, 2, Figs. 1-5). 



5a. Polyangium cellulosum var. ferru- 

 gineum Mishustin, 1938. (Microbiologia, 

 7, 1938, 427.) 



fer.ru. gi'ne.um. L. adj. ferrugineus of 

 the color of iron rust. 



Vegetative cells: Long, flexible cells, 0.8 

 to 1.2 by 3.0 to 5.0 microns. Become short- 

 ened and highly refractile during fruiting- 

 body formation. 



Fruiting bodj-: Composed of numerous 

 cysts having definite wall. Mass of rods has 

 a yellowish tinge, and the cysts are colored 

 reddish yellow. Color probably confined to 

 the cyst walls. Cysts round or egg-shaped, 

 or may be angular due to pressure. Each 

 cyst contains numerous shortened rods. 

 Cysts usually 12 to 40 microns in diameter. 

 Numerous cysts grouped into fruiting bodies 

 having bright red or drabbish red color when 

 ripe. Form of fruiting body variable: most 

 commonly rounded, ellipsoidal or biscuit- 

 shaped, sometimes sausage-shaped. Cysts 



confined by an orange-colored slime mem- 

 brane or envelope. No cystophore present. 

 Fruiting bodies not easily broken up. Vary 

 in size from 80 to 240 microns. 



Vegetative colony: On silica gel with cel- 

 lulose, at first pale pink. After six days 

 fruiting bodies of red color appear together 

 with free cysts and many non-encysted 

 shortened rods. Fruiting bodies numerous 

 at center of colony and later form in con- 

 centric rings around center. Margin of col- 

 ony composed of vegetative cells; periphery 

 pink. Mature colonies 2 to 5 cm in diameter, 

 bright red, becoming drabbish red; pigmen- 

 tation appears to be confined to limited 

 areas. Surface dull, moist. Margin not defi- 

 nite. 



Physiology: The cellulose at the center of 

 the colony is completely destroyed, whereas 

 that under the remainder of the colony is 

 not entirely broken down. 



The author considers this a color variant 

 of Polyangium cellulosum Imsenecki and 

 Solntzeva. 



Source: Isolated from the black soils of 

 Eastern European Russia. 



Habitat: Soil. Decomposes cellulose. 



5b. Polyangium cellulosum var. fuscxim 

 Mishustin, 1938. (Microbiologia, 7, 1938, 

 427.) 



fus'cum. L. adj. fuscus dark, tawny. 



Vegetative cells: Identical with those of 

 Polyangium cellulosum var. ferrugineum. 



Fruiting body: Composed of individual 

 cysts, each with a separate cyst wall, and 

 held together by a common slime membrane 

 or envelope. Shortened, rod-shaped spores 

 enclosed within the cyst walls. Cysts form- 

 ing outside the large walls. Cysts forming 

 outside the large masses usually rounded; 

 those within often polygonal or angular. 

 Cysts 5 to 24 microns long, ellipsoidal or 

 egg-shaped. Encysted cells give cysts gran- 

 ular appearance. Ripe cj^sts brown to light 

 brown in color; immature, yellow to pink. 

 Fruiting bodies pinkish yellow when young, 

 becoming brown when ripened. Considera- 

 ble variation in form: round, ellipsoidal or 

 sausage-shaped, and from 50 to 80 microns 

 up to several hundred microns. Outer slime 

 envelope often indistinct; no dried slime 

 noticeable between the cysts. 



