Miscellaneous. 210 



Two new Generic Types of the Families Saprologniese and 

 Peronosporeae. By MM. E. K,oze and M. Coknu. 



The authors remark that it is questionable whether the Sapro- 

 legnieae should be referred to the algse or the fungi. They think that 

 one of their new genera furnishes an argument in favour of the 

 latter. It is an endophyte, parasitic upon the smallest of our pha- 

 nerogams, TFo/^a Michelii, Schleid. {Lemna arr/i/rct, Linn.), and pre- 

 sents some characters belonging both to the Saprolegniese and Pe- 

 rouosporesD, so that it may to a certain extent be regarded as inter- 

 mediate between the two families. They name it CystosipJwn 

 pythioides. 



Its mycelium, which traverses the cells of iheWolffia by perfo- 

 rating their walls, developes the two kinds of reproductive organs 

 (sexual and asexual) which have already been indicated in the 

 species of this family. The first mode of reproduction terminates in 

 the formation of an oospore, the thick epispore of which resembles 

 that of the oospores of the Peronosporeae. This oospore originates 

 here, however, from the fertile union of the antheridian and oogonic 

 plasma, effected by means of a short process emitted by the antheri- 

 dium, which penetrates into the oogonial cavity. 



The so-called asexual reproduction of Cystosiplion is effected by 

 means of zoosporangia. These are represented by vesicles which 

 terminate certain branches of the mycelium in peripheral cells of 

 the Wolffia. When mature, each of these vesicles, which is isolated 

 by a septum from the rest of the mycelium, emits a tube which runs 

 perpendicularly to meet the cellular wall separating it from the 

 water. This flattens itself against the cellulose membrane, which it 

 perforates by an cxosmotic action, and then grows out into the 

 water until its extremity becomes stationary and slightly thickened. 

 The plasma of the zoosporangium is then instantaneously diffused in 

 this extremity of the tube in the form of a plastic spheroid, which in 

 a few minutes contracts and shows a very delicate enveloping mem- 

 brane continuous with the tube. The following phenomena arc then 

 rapidly witnessed in the interior of this vesicle : — A network of clear 

 lines indicates the segmentation which takes place in the plasmic 

 mass, and the cilia appear ; the segments separate from each 

 other and constitute the zoospores ; these agitate their cilia, and 

 move more and more rapidly ; lastly a portion of the wall of the 

 vesicle becomes absorbed and the zoospores escape. Their move- 

 ments last for about half an hour ; they then become spherical, 

 lose their cilia, become clothed with a membrane, and germinate by 

 emitting a tube. This germinative tube then penetrates by perfora- 

 tion into the cells of healthy fronds of Wolffia, where it is developed 

 into a mycelium. 



The Peronosporese, to which the second new generic type belongs, 

 have hitherto included only the genera Cystopus and Peronoi^pora: 

 The endophytal fungus, parasitic on Erigeron canadense, Linn., de- 

 scribed by the authors imder the name of Basidiopliora entospora, 

 is distinguished at the first glance from the above genera by its 



