58 



PLASM ODIOPH OR ALES 



Spoiigospora suhterranea was the first species of 

 the Plasmodiophoraceae to be reported in the litera- 

 ture, but it was not recognized as a member of this 

 family until about fifty years later. It was first re- 

 ported, in part by Wallroth in 18-t2, but he had 

 apparently found it tiie year before as is indicated in 

 Bartling's (18H) discussion. As is sliown in the 

 synonomy above, it was rediscovered a number of 

 times shortly afterwards in connection with otlier 

 fungi in scabby lesions of potatoes, and included in 

 various genera. It was not until 1886, however, that 

 Brunchorst first recognized it as a species of the 

 Plasmodiophoraceae. For a considerable number of 

 years a long controversy raged about its identity 

 and synonj'my, which has been fully reviewed by 

 Lagerheim, Massee, Pethybridge and Cook, and 

 need not be discussed further here. 



S. CAMPANULAE (Ferdinandsen and Winge) Cook, 

 1933. Arcli. Protistk. 80: 2lo. 

 Clathrosorus Camija indue Ferdinandsen and Winge, Lc. 

 PI. 21. 



Spore clusters or balls irregular, rounded or elon- 

 gate, 25-.50 /jL in diameter with large irregular chan- 

 nels. Spores spherical, 4-5.5 /jl, oval, irregular, trun- 

 cate, with fairly thick and slightly verrucose walls. 

 Plasmodia solitary in the host cell and only partly 

 filling it. multinucleate, irregular, 30-50 fi in diam- 

 eter, when mature ; segmenting into resting spores 

 which remain attached in a fairly loose spore ball. 

 Zoosporangia and zoospores unknown. 



Parasitic on the roots of Campanula rapiinculoides 

 in Denmark, causing numerous single or confluent, 

 tubercle-like galls. 



This species has been reported but once. Whether 

 it belongs in Sponc/ospora, as Cook believed, or rep- 

 resents a new genus is obviously questionable in light 

 of present-day knowledge, but since its spore clus- 

 ters are reported to be loose, irregular, round or 

 elongate balls (fig. 38), it may be conveniently in- 

 cluded here for the time being. It occurs in the cortex 

 of the roots (fig. 38), and although the central cylin- 

 der mav be distorted, it is never parasitized. The 

 infected cells are only slightly if at all enlarged (fig. 

 40-12) and do not divide, but the presence of the 

 parasite nonetheless stimulates adjacent healthy 

 cells to divide. The galls are thus almost entirely the 

 result of cell multi])lication. The nucleus of the host 

 cell is often enveloped by the parasite (fig. 10), but 

 it does not become greatly enlarged. 



According to Ferdinandsen and Winge, meiosis 

 occurs during the last two nuclear divisions in the 

 Plasmodium preceding sjiore ball formation. They 

 did not, however, count the number of chromosomes 

 nor observe plasmogamy and karyogamy, .so that 

 their conclusions are not based on adequate observa- 

 tions. 



Another species of Sponc/ospora was recently re- 

 ported and described by ,1. T. Barrett in a brief 

 paper presented before a joint meeting of the Ameri- 

 can Mycological and Phytopathologieal Societies at 

 Philadelphia, Pennsylvania, December 30. 1910. Dr. 



Barrett has not completed his study of this species, 

 but he has graciously allowed me to include a few 

 notes on the essential features of its life cycle. This 

 species parasitizes Cotula australis in California and 

 causes cons])icuous galls or nodules on its roots. 

 Barrett accordingly named it .S'. Cotidae. In germina- 

 tion each resting spore produces a single zoospore 

 with two unequal flagella as in <S'. suhterranea. The 

 zoospores infect the host and eventually give rise to 

 zoosporangia which in turn form motile cells of the 

 same type and character as the zoospores produced 

 by the resting spores. Barrett found fusion stages of 

 the zoospores or gametes from the sporangia in fixed 

 and stained material, but he has not yet observed 

 plasmogamy in living material. Whether or not the 

 sporogenous plasmodium is thus zygotic in origin is 

 uncertain at present. The spore balls or cystosori 

 and resting spores, nevertheless, usually follow the 

 sporangial stage and thus complete the cycle of de- 

 velopment. 



ADDITIONAL BIBLIOGRAPHY: SPONGOSPORA 



Bartling, E. 1841. Versammelung. Deut. Nat. u. Aerzte zu 

 Braunschweig im September 1841. Vieweg und Sohn, 



184:3. 



Ferdinandsen, C. 19-'3. Tidsskr. f. Landokonomi. 19J3. 



Home, A. S. 1930. Ann. But. 44: 199. 



.lohnson, T. 1907. Econ. Proc. Roy. Dublin Soc. 1: 345. 



. 1909. Sci. Proc. Roy. Dublin Si>c. n. s. 12: 165. 



Khrohrykb, \. D. 1938. Summ. Sci. Res. Inst. pi. protect. 



for' 193()- 1938: -21. 

 Kunkel, I.. O. 1915. Jour. Agr. Res. 4: ^65. 

 I.edingham, G. A. 1935. Nature 135: 394. 

 Massee, G. 1908. Jour. Bd. Agrio. England 15: 594. 

 Melhus, I. E., J. Rosenbaum, and E. S. Schultz, 1916. Jour. 



Agr. Res. 7: -'13. 

 Osborn, T. G. B. 1911. Ann. Bot. 25:211, 337. 

 Rybakova, S., and H. Nedosliivina. 1936. White Russ. 



Acad. Sci. Inst. Biol. Sci. Minsk 1936: 57. 

 Sharpies, A. 1933. Malayan Agric. Jour. 11: 367. 

 Truscott, J. H. L. 1934. Canad. Jour. Res. 11: 1. 

 Weber, A. 1933. Tomatsygdonime. Copenhagen. 

 Wild, N. 1939. Phytopath. Zeitschr. 1: 367. 



LIGNIERA 



Maire and Tison, 1911. C. R. Acad. Sci. Paris 

 152: 206. 



(plate 1 1) 



Resting spores not consistently aggregated in cys- 

 tosori of characteristic shajie and structure ; vari- 

 ously-shaped with relatively thin hyaline or colored, 

 smooth or verrucose walls. Plasmodium relatively 

 small, ])artly or comi)letely filling tlie host cell; seg- 

 menting into either zoos))orangia or one or more 

 cystosori; schizogony reduced or lacking (?). Zoo- 

 sporangia numerous in a cell and usually grouped to- 

 gether, small and variously-shaped ; opening by a 

 rupture of the wall. Zoosj)ores from sporangia ]iyri- 

 forni. Germination of resting spores doubtful or un- 

 known at ])resent. 



