— 308 — 



two opposite points of the spore, are often much ramified and pro- 

 duce — partly intercalarly, partly terminally on side-branches — swel- 

 lings, the further development of which we have not happened to follow; 

 after analogy from other species however (cfr. Cladochytrium tenue Nowak.) 

 they will most likely develop into zoosporangia. A germination of this 

 type is evidently occurring as an exception; the principal rule is that the 

 wintered resting spore itself is becoming a sporangium. This process 

 goes on rapidly, for even- on examining a great quantity of material at 

 short intervals it is difficult to come across spores on the germinative 

 stage. Either they are seen entirely unchanged or the germination has 

 finished, and the evacuated burst exospores are only remaining. We 

 have happened, however, to find different stages of the metamorphosis of 

 the resting spores, and we are able to ascertain that the course of 

 development is as follows : When the resting spore is approaching its 

 metamorphosis into sporangium, its contents become somewhat nebulous 

 and are soon divided into polygonal fields with thin dissepiments; each of 

 these fields represents a zoospore on the point of formation. At this 

 stage the exospore begins to vault forth (fig. e). Soon the young zoo- 

 spores are becoming rounded, and coincident with the shooting forth of 

 the endospore in a coUum the zoospores are emancipated as globose or 

 ellipsoidal bodies, 6 — 8 fjt diam., with an excentric oil-drop. They are 

 pressed forth through the collum, which is soon bursting. 



When having in the above report always mentioned the spores being 

 formed in the sporangium as zoospores, we ought to point out that we 

 have not happened in any case to see their flagellum or to observe 

 surely their swarming-stage. After analogy from other Cladochytrmm- 

 species with swarming spores, which lying in the sporangium have quite 

 the same aspect as ours, we are allowed to conclude that our fungus 

 really has zoospores, the more so as it is very difficult to observe swarming 

 stages at all. 



March 6. — In a pond in the Botanical Garden are collected turions 

 of Myriophtjllum verticillatum. These are on an average 4 — 5 cm. in 

 length having 4 — 5 whorls of leaves expanded (with roots at the lower 

 ones). Some of the turions were still fastened to the decaying stem of 

 the mother-plant, while other ones were anchored to the bottom by means 

 of mire, lying around the lower recurved leaves. The plants fished up 

 are placed in two wide cylinder-glasses, in the first one 23 plants to- 

 gether with a great quantity of the wintered resting spores, in the second 

 one 10, which are to be control-plants and are let free from infecting- 

 material; for the rest Cladochytrium has never occurred in the very 

 luxuriant growth of Myriophyllmn, which is at hand in the above 

 named pond. 



