1030 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Ochre yellow formations resembling 

 fruiting bodies by 5 to 6 days. Many 

 free cysts at center of colony. Later 

 colony becomes pale dirty-yellow, while 

 periphery remains bright yellow. Some- 

 times one or two brightly pigmented 

 rings consisting of agglomerations of 

 fruiting bodies are found in older colonies . 

 Mature colonies 1.5 to 3.0 cm in diameter. 



Physiology : Filter paper completely 

 destroyed at center of colony. De- 

 veloped better below pH 7 (around pH 6) 

 than others of the species. 



Source : Isolated from soils of the 

 Timiriazev Agricultural Academy. 

 Common in podzol soils. 



Habitat : Digests organic matter in soil. 



6. Polyangium simplex Thaxter. 

 (Myxobacter simplex Thaxter, Bot. Gaz., 

 18, 1893, 29; Thaxter, Bot. Gaz., 37, 

 1904, 414.) 



Etymology : Latin simplex, simple, i.e., 

 not compound. 



Swarm stage (pseudoplasmodium) : 

 Rods, large, cylindrical, rounded at 

 either end, 0.7 to 0.9 by 4 to 7 microns. 



Fruiting bodies : Cysts single, very 

 large, 250 to 400 microns, bright reddish 

 yellow, irregularly rounded. Rods flesh 

 colored in mass. Upon pressure ad- 

 hering together in sheaves. 



Source and habitat : Found by Thaxter 

 (loc. cit.) in U. S. A. on very wet wood 

 and bark in swamps. 



7. Polyangium ochraceum Krzemien- 

 iewski. (Acta Soc. Bot. Poloniae, 4, 

 1926, 34.) 



Etymology : Modern Latin from Greek 

 ochra, yellow ochre, hence ochraceous. 



Swarm stage (pseudoplasmodium) :Not 

 described. 



Fruiting bodies: The orange to light 

 red fruiting body in form of a single 

 spherical or oval cyst 60 to 80 by 50 to 130 

 microns, each with a thick j'ellow-brown 

 membrane. The cyst content often 

 (particularly in the oval cysts) is con- 

 stricted by the membrane which pene- 



trates deeply. From the side the cyst 

 appears to be divided. Rods in cysts 

 0.5 by 4 to 8 microns. 



Source and habitat : From sterilized 

 rabbit dung on soil (Poland). 



Illustrations : Krzemieniewski {loc. 

 cit.) PI. V, Fig. 50, 51. 



8. Polyangium fusciim (Schroeter) 

 Thaxter. (Cystobacter fuscus Schroeter, 

 in Cohn, Kryptogamenflora v. Schlesien, 

 3, 1, 1886, 170; Thaxter, Bot. Gaz., 37, 

 1904, 414.) 



Etymology: Latin fuscus, fuscus, 

 brown. 



Swarm stage (pseudoplasmodium): 

 Rods slender, elongate, 0.6 by 5 to 12 

 microns. Grows readily on agar, also on 

 dung agar. Baur states rods arc 15 to 20 

 microns in length and move about 2 to 3 

 microns per minute in hanging drop, on 

 agar 5 to 10 microns per minute. 



Fruiting bodies : Cysts flesh-colored 

 when young, chestnut brown when ripe, 

 spherical, about 60 microns (Thaxter, 50 

 to 150 by 50 to 70 microns) in diameter, 

 with definite membrane, lying in con- 

 siderable numbers in large sori, usually 

 30 to 40 sometimes up to 100. The slime 

 envelope is much more delicate and 

 evanescent than in P. vitellinum. Oc- 

 casionally a form is found with cysts 

 measuring 100 microns: under these often 

 lie kidney shaped cysts even 150 microns 

 in length; apparently, a variety. Rods 

 in cysts -about 0.8 to 1.5 by 3 to 3.5 

 microns. Cysts (Baur) on dung decoc- 

 tion break in 10-12 hours, and rods pour 

 out, apparently passively at first. 



P.fuscum var. velatum Krzemieniewski 

 differs from the type in that the mem- 

 brane is thin, separated from cysts, 

 folded. 



Source and habitat: Thaxter (Bot. 

 Gaz., £3, 1897), on rabbit dung from 

 southern California. Kofler (Sitzber. d. 

 Kais. Akad. Wiss. Wien. Math. -Nat. 

 Klasse., 122 Abt., 1913, 845) on rabbit 

 dung, Vienna. Jahn (Die Polyangiden, 

 Geb. Borntraeg., 1924), common on dung, 



