16 ARKIV FÖR BOTANIK. BAND 12. NIO 9. 



and compared them to those of the Urticaceae, but Rosa- 

 NOFF is of opinion that they are the remains of a parasitic 

 mycehum. These were all the results arrived at by the two 

 authors. 



The next time we find this fungus mentioned in the 

 literature is in 1907 in »Botanisk Tidskrift». On an excur- 

 sion the fungus was found (on Sept. 15*^) by Dr. C. H. Os- 

 tenfeld on Callitriche autumnalis in the small stream near 

 Rönnekro and in the lake Ringsjö, both places in the 

 neighbourhood of Sjöholm station (Skåne, Sweden) and was 

 set down (1. c.) as a new myxoraycet, Sorodiscus Callitrichis 

 which Lagerheim proposed to describe later on under this 

 designation. — Lagerheim was namely perfectly well ac- 

 quainted with this fungus long before 1907 as in the year 1893 

 he had already found it on Callitriche vernalis growing on 

 most soil near Bjerkeng in Målselvdalen (the valley of 

 the Måls-river) in the county of Tromsö, Norway, and 7 

 years later (1900) he had collected material of it in the same 

 place. He only found a few infected plants, but material 

 from these were fixed with »Merkel» and Lagerheim got so 

 far in his investigations of the fungus that he took a number 

 of cuts on the microtome which convinced him, that Soro- 

 discus was a new endophytic mycetozo. 



Finally the fungus is mentioned in a third place, as 

 Maire and Tison in their latest published work^^ cite the 

 above mentioned memoir by Kareltchikoff and Rosanoff. 

 They write: ». . . Kareltchikoff et Rosanoff (1870) ont 

 décrit des tumeurs produites sur Callitriche autumnalis L. 

 par un organisme qui, d'apres leur description, pourrait bien 

 étre une Plasmodiophoracée.» — This assumption was pre- 

 sumably essentially confirmed during a visit which these 

 authors paid to Professor Lagerheim in Stockholm a few 

 years ago. 



The result of my observations on the fungus for the 

 most part agree with the conditions in Sorosphaera Veronicae, 

 yet with the modifications stated above. After Lagerheim 

 had cut up the material into cuts of 2 — 7 [x it was stained 

 with Safranin-Gentianviolet-Orange, Fuchsin-Toluidinblue and 

 Ironalun-Hsematoxylin, of which methods the first named 

 proved most successful. 



