SIKDI.IMIIIACK.VK 



68 



Sawada, K. 1919. Hull. Agr. Bxpt. Stat. Formosa III. Stein, F. R. 1878. Der Organismus des Infuslonsthlere III, 



1919, Ibid. 19, »bt. I, .'. Leipzig. 



Shanor, I .. 1939. Jonr. Ellsha Mitchell Sci. Soc. 55: 179. Tehon, It. It., and II. A. Harris. 1941. Mycologia 33: 18. 



1940, ibid. 56: 165. Valkanov, A. 1931. Arch. Protistk. 73:361. 



Sparrow, I'. K. 1939. Mycologia 24: »68. 1933, ibid. 25: Varitchak, B. 1931. C. H. Acad. Sci. Paris. 192:371. 



513. [939, ibid. 31:443. 1943, ibid. 34: 116. Wildeman, de, !•'.. 1891. Bull. Soc. Hoy. Bot. Beige. 30: 

 Sydow, H.. and P., and E. J. Butler, 1907. Ann. Mycol. 169. 



,- ): is , Wolf, F. T., and F, A. Wolf. 1941. I loydia 1: -'To. 



Chapter V 



Sirolpidiaceae 



Sparrow, 1942. Mycologia 34: 11 .'5. 



This family was established by Sparrow for the 

 genera Sirolpidium and Pontisma which Petersen 



( '()."> ) had previously made the basis of the family 

 Holochytriaceae. Thirteen years earlier, however, 

 Fischer ('92) had proposed the same family name 

 as an alternate tor the Ancylistaceae to include My- 

 zocytium, Achlyogeton, I. age nidi urn and Ancylistes. 

 There was thus no agreement between Petersen and 



Fischer as to which genera comprise the Holochy- 

 triaceae, but they nevertheless placed it in the My- 

 cochytridiales. While the Holochytriaceae may have 



priority over Sparrow's family name, the Suffix 

 chytriaceae carries the connotation that these fungi 

 are chytrids. which is incorrect in light of present- 

 day knowledge. The name is therefore no longer ap- 

 propriate and descriptive. The present author is ac- 

 cordingly adopting the Sirolpidiaceae in preference 



to the 1 loloch ytriaccae. but only as a temporary con- 

 venience because it is not at all certain that Sirol- 

 pidium and Pontisma constitute a distinct family. 

 So far only vegetative thalli, zoosporangia, .and zoo- 

 spores have been adequately described, and very 

 little, if anything, conclusive is known about the 



n sting spores and their method of development. 



Since the thalli and zoospores of Pontisma an not 

 strikingly different from those of Sirolpidium, the 

 two genera are herewith merged, and the former 

 genus is reduced to a synonym of the latter. Peter- 



Senia in a limited sense is also included in this fam- 

 ily, because its thalli are frequently similar to those 



oi Sirolpidium. Obviously, this arrangement also 

 may be completely invalidated by future discoveries. 



As the family is herewith presented it includes two 



genera of incompletely known holocarpic species 

 characterized by olpidioid or elongate and some- 

 times filamentous thalli which may or may not un- 

 dergo segmentation. In some species the segments 



separate and become transformed directly into zoo 

 sporangia. 



SIROLPIDIUM 



Petersen. 1905. Overs. Kg!. Dansk. Vids. Selsk. 

 Fori). 5: 478. 

 Pontisma, Petersen, I.e., p. 482. 



(plates 16, 17) 



Thallus predominantly intramatrica] but becom- 

 ing partially extramatrical under certain conditions; 

 olpidioid or elongate and filamentous; transformed 

 directly into a single sporangium or undergoing sep- 

 tation and fragmentation to form a row of separate 

 sporangia; fragmentation reduced or lacking in some 

 species. Zoosporangia usually numerous in the host 

 cell, variable in size and shape with one simple or 

 branched exit tube which varies markedly in length 

 and may extend considerably beyond the surface of 

 the host wall, or occasionally opening within the host 

 cell. Zoospores isocont with the flagella attached at 

 or near the anterior end (?) and extending in op- 

 posite directions; swarming within the sporangia. 

 emerging fully developed and swimming directly 

 away; occasionally liberated within the host cell. 

 Resting spore doubtful or unknown. 



This genus was created by Petersen for de 



Bruyne's Olpidium Bryopsidis after he had found 



that the zoospores arc biHagcllate instead of uni- 

 flagellate. In the writer's opinion, I'ontixina docs 



not differ fundamentally from Sirolpidium, and on 



the basis of present-day knowledge it may well be 

 merged with the latter genus. Sparrow (':>!) main 

 tained that it differs from Sirolpidium by its more 

 irregularly tubular thallus and the fact that the 

 segments ilo not separate and form isolated and free 

 sporangia. Nevertheless, both he and Petersen re- 

 port that in exceptional cases the thalli appear to 

 fragment and give rise to trie or loosely connected 



