CONTKIBUTIONS FROM THE WISLEY LABORATORY. 367 



^ Masses, however, m his text-book, pubHshed in 1910, writes that 

 both Potter and himself were mistaken in their identification of the 

 fungus. He states that he had written to Schilberszky on the sub- 

 ject, and had received a reply to the effect that the parasite was not his 

 Chrysophlyctis endohiotica. He had unfortunately not kept Schil- 

 berszky's reply, and for this reason it cannot be quoted verbatim. 

 Massee therefore changed the name to Synchytrium solani, Massee. 



Owing to the fact that so, many conflicting accounts had appeared 

 relative to the supposed Chrysophlyctis, Professor J. B. Farmer sug- 

 gested that a communication be sent to Schilberszky, together with 

 specimens of diseased tubers and microscopic preparations of the 

 organism, with a view to finally settling the question of identity. 

 Accordingly on February 21, 1911, a letter was sent, but up to the 

 present (November 20, 1911) no reply has been received. It will be 

 remembered that no reply was sent to Miss Lorrain Smith's letter of 

 1902. 



, It is necessary, therefore, to rely upon Schilberszky' s original, 

 somewhat meagre, description. Meagre as it is, however, and without 

 illustration, I have no hesitation in believing that his organism and ' 

 the parasite known to be the cause of potato tumour in Great Britain 

 and Ireland are identical. There remains but one apparently serious 

 difficulty. This is oonoemed, however, with the symptoms of the 

 disease, not the organism. SchilberszkyI states that another tuber — 

 not the one from which he obtained his description of the organism — 

 representing an older stage in the progress of the disease, showed signs 

 of corrosion or hollowing-out. This condition does not obtain at all 

 in potato tumour. It is a characteristic feature of tubers attacked witli 

 Spongospora sola7ii — the canker parasite. It seems highly probable 

 therefore that a potato affected with canker was among those sent 

 to Schilberszky from Upper Hungary. 



There yet remains to be considered the evidence brought forward 

 by PercivalJ in favour of the transference of Chrysophlyctis to the 

 genus Synchytrium. Percival sums up his position very briefly. 

 He states that the parasite agrees in practically all respects with Sy7i~ 

 chytrium — in " the form of its swarm-spores, its growth within the 

 invaded tissues of the host, the production of sori of sporangia, and the 

 germination of the latter . . . moreover, the cytology of the parasite 

 supports the proposal." Before going any further it seems advisable 

 to revert for a moment to Synchytrium itself, and to set forth the chief 

 known characteristics of the genus. The following types of repro- 

 ductive bodies have been described : — 



1. The sporangium-sorus. A reproductive organ, formed from the 

 vegetative body, which contains a number of sporangia. 



2. Besting swarm- sporangia (dauersporen). These give rise directly 

 to zoospores. 



* G. Massee, Diseases of Cultivated Plants and Trees, p. 100. 

 t K. Schilberszky, Ber. d. Deut. Bot. Gesellsch., xiv. (1896), p. 36. 

 t I.e. p. 444. 



