28 ARKIV FÖR BOTANIK. EAXD 1*2. N:0 9. 



myxoplasms with one small nucleus are seen in the cells of 

 the alga which must be assumed to have been formed by 

 swarming-spores which forced their way in recently. Several 

 such small plasms may be found together in one cell, and 

 JuEL considers it possible that later on they fuse into a 

 fusion-plasmodium. Moreover he finds both small myxo- 

 plasms with one larger nucleus and larger myxoplasms with 

 several nuclei. The former he accounts for in this way that 

 the nuclei in the above mentioned uninucleate cells have 

 grown in size. (Probably they are meronts !) The latter have 

 either arisen by fusion of the uninucleated ones or by nuclear 

 divisions having taken place and the nuclei having grown in 

 size. This last hypothesis is, judging from the hitherto known 

 Plasmodiophoraceae, the correct one. 



JüEL has likewise examined myxoplasms with many small 

 nuclei and he is of opinion, that possibly they arise in this 

 way that the large nuclei in the plurinucleate amoebae suc- 

 cessively divide into smaller ones. — In case these are not 

 just young ones, plurinucleate amoebae representing the first 

 schizont-generations, which, however, the want of caryosome 

 in the nucleus in the illustration seems to deny, then Juel's 

 view is correct. The nuclei of this stage are, however, ac- 

 cording to his figures, remarkably small. — 



About the next stage be remarks that: »Das Plasmodium 

 ist in eine grosse Anzahl von amöben-ähnlichen Körpern mit 

 je einem Zellkern aufgeteilt. Die Umrisse dieser Zellkörper 

 sind im Präparate recht undeutlich» . . . These »plasmodia» 

 evidently represent the last phase of the »chromatical stage» 

 of the true Plasmodiophoraceae. — The myxoplasms surround 

 themselves with a wall, and inside this are either formed 

 closely placed spindle-formed uninucleate small cells which 

 quickly become rounded spore-mother cells — or scattered 

 spindle-formed cells which probably also later on — in some 

 cases certainly — ■ are converted into spore-mother cells. These 

 walled plasms with scattered nuclei frequently stretch in a 

 net-like way through a greater number of the cells of the 

 host-plant, so that the plasma before it became walled must 

 have penetrated a great number of tlie cell-walls. 



The closely placed, uninucleate and walless spore-mother 

 cttls are often intermingled with a few sterile cells which go 

 to ruin. The nuclei and the spore-mother cells now divide 



