WINGE, CYTOLOG. STUDIES IN THE PLASMODIOPHORACEiE. 25 



by Jahn^ 1907. Here Jahn found 4 nuclei in the mature 

 spore and these divide at the germination into 8 nuclei, 

 whereupon 8 s warming-spores are formed. Johnsson's ob- 

 servations are, however, contradicted by later observations 

 (see below!). — In connection with this fungus must be men- 

 tioned a memoir by Horne.^^ The author has on Pteris found 

 an organism in the cellular tissue of the rhizome-apices. Ac- 

 cording to his description and bad illustrations we have 

 reason to believe that all his »bodies» are oil-globules, pre- 

 cipitation-, degeneration- and other phenomena in the tissue 

 of the host-plant. Recently both Osborn^2,24 ^^^ Horne^^ 

 have given their opinions on Spongospora. We here cite some 

 of Osborn's results: The amoebae are only distributed pas- 

 sively in the host-plant (by the cell-divisions of the host- 

 plant) — not actively as Massee^^ assumes. Polar radiations 

 from the nuclear spindles do not occur in Spongospora nor 

 centrosomes at the vegetative stage. The uninucleate nuclei 

 of the small amoebae divide amitotically, the amoebae also 

 divide, hence only small amoebae are found. At the close 

 of the vegetative phase they fuse and form a plasmodium in 

 which the nuclei disappear, so that only vacuoles remain 

 (»akaryote stage»); the chromatin moves out into the plasma. 

 Totally new nuclei are formed and these fuse two and two. 

 The fusion-nucleus divides mitotically twice. The spores are 

 uninucleate. — Osborn never succeeded in bringing the spores 

 to germination, but according to Massee (1. c.) the contents 

 of the spore is at the liberation of a regular roundish form 

 with a few projecting pseudopodia. The movement is slow 

 and only lasts a short time. — Osborn (1. c.) declares that 

 a caryogamy certainly will be found also in other Plasmo- 

 diophoraceae(!). — From Osborn's detailed figures and de- 

 scriptions it seems as if a caryogamy really takes place in 

 Spongospora — and in this case the fungus must be removed 

 from the Plasmodiophoraceae. A revision of Osborn's results 

 would be of great interest. 



Pavillard^^ also supposed, that a caryogamy would be 

 found in all the Plasmodiophoraceae. But w^e do not agree 

 with this author when he writes about this question in his 

 last notice^"^: . . . cette absence (of the caryogamy) est loin 

 d'etre démontrée . . .» If a caryogamy at this stage is 



