430 GENERAL SYSTEMATIC BACTERIOLOGY 



It may be noted that Smith (1905, p. 174) rejects the name Pollen- 

 dera (which he spells Pollendra) at the same time he proposes Aplano- 

 bacter. 



Pollendra. A spelling of Pollendera (q.v.) used by Erwin F. Smith 

 (1905, p. 174). 



Polyangium. This genus was first created by Link (1795, p. 40) 

 according to Zukal (1897, p. 550) for the species P. vitellinum. He 

 regarded it as a species of fungus, and as such it appeared in several 

 floras and works on fungi. What is evidently the same species was 

 described later by Thaxter (1892, p. 394) as Myxobacter aureus. He 

 first recognized the true affinities of the organism as a genus of the 

 Myxohacteria, and that it is not a true fungus, nor, as had been urged by 

 Bonordon, an insect egg. That the genus Myxobacter of Thaxter is a 

 synonym of Polyangium Link was pointed out by Zukal (I.e.). Myxo- 

 bacter aureus Thaxter therefore became Polyangium vitellinum Link. 

 This explanation was accepted by Saccardo (1899, p. 844) who states: 



Polyangium Link Sjdl. VII. p. 47. (inter dubia) Hue ducendum est genus Myxo- 

 bacter Thaxt. Syll. XI. p. 461 cuius species M. aureus Thaxt. coUidit cum Poly- 

 angio vitelline Link jam ab anno 1795 descripto, sed huiusque inter dubia, 

 relato. 



This was accepted later by Thaxter (1904, p. 37). 



Cystobacter Schroter (q.v.) is given by Thaxter as a synonym, in 

 part. Seven species are recognized, as follows: Polyangium vitellinum 

 Link, P. simplex Thaxter, P. fuscum (Schroeter) Thaxter, P. septa- 

 tum Thaxter, P. compositum Thaxter, P. sorediatum Thaxter, and P. 

 primigenium Quehl. 



The genus is apparently valid. It is so recognized by Smith (1905, 

 p. 165) and by Quehl (1906, p. 16). 



The diagnosis of the genus given by Thaxter is: "Rods forming large, 

 rounded cysts, one or more free within a gelatinous matrix raised above 

 the substratum." Together with the genera Myxococcus and Chron- 

 dromyces, it constitutes the family Myxobacteriaceae. 



Buchanan (1918, p. 542) included this as the second genus of the 

 family Myxobacteriaceae with the following description. 



Rods forming large rounded cysts, one or more, free within a gelatinous matrix 

 raised above the substratum. 



The type species is Polyangium vitellinum Link. 



Bergey et al. (1923, p. 416) followed Buchanan. 



