12 ARKIV FÖR BOTANIK. BAND 12. N:0 9. 



verlaufen Reste des zersprungenen Gefässbündelringes in 

 Form kleiner Cribrovasalbündel. Sie haben einen geschlän- 

 gelten Verlauf, sind oft sehr verzerrt und bestehen haupt- 

 sächlich aus oft unvollständig und unregelmässig ausgebildeten 

 Spiralgefässen; Porengefässe, die im normalen Gefässbündel- 

 ring das Succedanholz bilden, sind spärlich oder fehlen 

 gänzlich.» 



As regards the infection of Sorosphaera Veronicae Blom- 

 FiELD and Schwartz-^ report that it takes place near the 

 »growingpoint», and later Maire and Tison-^ arrive at the 

 same result (»au voisinage du point végétatif») .It is, however, 

 not allowable to speak of a »growingpoint» as regards a 

 phanerogamic plant; hence it it impossible to know, whether 

 the authors mean the most pronounced growing-zones or the 

 point of the stem. Blomfield and Schwartz (1. c.) made 

 a simple trial, which succeeded. Some seeds of Veronica were 

 sown in a pot and were spurt with water containing spores 

 from dry tumours of Sorosphaera. The roots were never 

 attacked by the fungus. Unfortunately we don't know any- 

 thing about the germination of the spores and the infection 

 itself, which would be of great value for the knowledge of 

 the biology of the fungus. But all the phases from the time 

 shortly after the infection until the maturity of the spores 

 are fully elucidated by Maire and Tison and likewise by 

 Blomfield and Schwartz. The last named authors pu- 

 blished their paper six months after Maire and Tison, and 

 independently they came to exactly the same result; the 

 French authors are but more explicit. We shall not dwell 

 on the interesting results, found by these authors; besides 

 on a large scale they correspond with the results of Nawa- 

 SCHIN (1. c.) on Plasmodiophora, except as regards the mistake 

 corrected as above mentioned by Prowazek (I. c). 



As regards my own studies in the cytology of this fungus 

 I may nearly in extenso confirm their results. Only two 

 points in the life-cyclus may be commented upon. In the 

 vegetative phase when the nuclei are in the prophase the 

 chromatin is divided into trophochromatin and idiochromatin, 

 the latter surrounding the former (fig. 65). According to 

 Maire and Tison the idiochromatin has the form of a ring. 

 By focusing up and down and by regarding the prophase 

 from different sides it becomes evident that the idiochromatin 



