30 ARKIV FÖR BOTANIK. BAXD 1*2. N:0 9. 



To say the least of it, this is to turn facts upside down. 

 XÉMEC seems totally to forget that »the sorosporangia» (the 

 spores) in the Plasmodiophoraceae are not formed until after 

 the two sporogonic divisions have taken place, while in So- 

 rot pidmm and Pyrrhosorus they are formed prior to these 

 divisions. In Sorolpidium the sporogonic divisions do not 

 take place until after this cell-amassment which Nemec affects 

 calling »Sorosporangienhäufen». . — It is thus not justifiable 

 to homologize these stages. It will be seen from the follow- 

 ing classification that the »cysts» occurring in the Plasmo- 

 diophoraceae are aggregations of spores, while in Pyrrhosorus 

 and Sorolpidium they are aggregations of walled spore-mother 

 cells. 



From Xemec's more detailed, but somewhat slovenly paper 

 (1. c.) it is evident, that his Sorolpidium is closely related to 

 Pyrrhosorus and the Plasmodiophoraceae. It is remarkable 

 that XÉMEC without any reservation terras the vegetative 

 divisions of this fungus »karyokinetische». It can not be 

 justifiable to term nuclear divisions which are characteristic 

 by the want of visible chromosomes and by the amitose-like 

 bipartition of the nucleolus (the caryosome) mitotical. Nemec 

 says: »Es lässt sich nichts ausfindig machen, was dartun 

 könnte, das der Nucleolus Material zur Bildung von Chro- 

 mosomen abgäbe.» There is, however, hardly any doubt that, 

 by closer investigations, Sorolpidium in this as in every other 

 respect will be found to resemble the Plasmodiophoracae. 

 Alone the circumstance that chromosomes and caryosomes 

 never occur simultaneously points in this direction. — Another 

 of Nemec's observations is unintelligible to us : »Plasmodio- 

 phora bildet keine Membran um ihren vegetativen Körper, 

 wenn sie sich zur Fortpflanzung anschickt. Die mit Plasmo- 

 diophora sicher verwandte Sorosphaera bildet jedoch eine 

 Membran. » Sorosphoera Veronicae, at any rate, does not 

 form any membrane but on the spores, and it must be due 

 to a misunderstanding when Nemec is of opinion that other 

 species do so. It deserves notice that Sorolpidium Beiae does 

 not produce hypertrophy in the host-plant, radiative pheno- 

 mena from the poles of the nuclei are not observed, but in 

 the apices of the nuclear spindle are seen distinct centrioles 

 which Nemec explains as swellings of the »CeZ/emembran». 



