48 • The Ohio Naturalist. [Vol. X, No. 3, 



general appearance is identical with that of the resting spores of 

 S3''nchytrium which Von Gutenberg has recently determined to 

 be chitinous. On account of the scarcity of material, how^ever, 

 michrochemical tests to determine its composition were not 

 undertaken. 



General Considerations. 



The relationships of Monochytrium are in the present state of 

 our knowledge regarcUng the Chytrids somewhat obscure. Its 

 method of parasitism and general structure are similar to those 

 of Synchytrium and, had the present plant been described with- 

 out reference to its cytology, the only difference between the two 

 genera that would have been noticed is the difference in seg- 

 mentation which in Synchyrium results in the formation of 

 zoosporangia each of which in turn gives rise to numerous 

 zoospores while in Monochytrium the zoospores are formed 

 directly, each cyst becoming a single zoosporangium. This 

 difference is however of itself sufficient to remove the plant from 

 the Synchytriaceae and place it among the Olpidiaceae. From 

 all the genera of this familv Monochvtrium ma}' be separated at 

 once by its habitat. All the other genera are parasites of 

 aquatic plants or animals except Asterocvstis which infests the 

 roots of the seed plants. 



So far as the writer is aware in no other plant has a conjuga- 

 tion of gametes been reported to occur after the votmg parasites 

 have infected their host. But when the cvtologv of the lower 

 organisms especially .of their early stages is better known' it may 

 be found that such a conjugation is not so rare as now appears. 

 It is quite possible that nianv forms now supposed to be non- 

 sexual may conjugate after infecting their host. The life history 

 of most species of Synchvtrium for example would seem to 

 demand some difference in constitution between the summer 

 sori and the resting spores similar to this belated conjugation of 

 Monochytrium; but if such a sexual act exists it is obvious that 

 in these cases the nuclei also must fuse. The continued inde- 

 pendence of the nuclei of the zygote may be more unusual but 

 when it is recalled in how few of the zygospores of the lower 

 plants are the actual conditions of the nuclei known, it is evident 

 that such a plasma conjugation may be more common than now 

 suspected. This long continuance of the apvlogamic phase in 

 Monochytrium cannot fail to recall the similar phenomena in the 

 nuclei of the higher fungi. Nothing could be of greater interest 

 than to determine the fate of these two nuclei in the germination 

 of the resting spore. Attempts at germination must however 

 wait upon more abundant material than is now available. 



It is hoped that an opportunity mav also be presented to 

 observe the zoospores in the living condition in order to deter- 



