238 BULLETIN 94. 



been dead for sometime, however, there will probably be seen 

 here and there on the hyphae a number of rounded or spherical 

 bodies, three to five times the diameter of threads of the mycelium 

 with which they are connected. These are reproductive organs of 

 the fungus and will soon be described. 



The characters of the mycelium alone are not in all cases suffi- 

 cient for the correct determination of the plant. L,et then this 

 preparation on the glass slip lie free in an abundance of water, and 

 place the slip in a small moist chamber sufficiently protected so 

 that the air in the chamber will not become dry by evaporation at 

 the point of contact of the two vessels. This can be avoided by 

 placing a sheet of wet filter paper between the cover and the edges 

 of the bottom vessel. A Petrie dish, such as is used in bacterio- 

 logical work, is excellent for the purpose. Some wet filter paper 

 should also be placed in the bottom and on this the support for 

 the glass slip can be placed. For hasty examination the material 

 can be teased out directly in the bottom vessel of the Petrie dish 

 in a little water, and then this can be placed on the stage of the 

 microscope whenever it is desired to examine it. 



In twelve to twenty-four hours if the preparation is again exam- 

 ined many threads of the fungus will be seen to have grown out 

 from the tissue and spread on all sides for a distance of one to 

 two millimeters in the surrounding water, now presenting the 

 characters noted above in a clear manner, except there are no con- 

 strictions of the hyphae corresponding to those where they pass 

 through the cell walls of the host. The branching is in an alter- 

 nate or irregularly monopodial fashion. There will also be seen 

 numbers of the rounded bodies noted above on the mycelium, both 

 within the tissue and on the mycelium which is growing free in 

 the water around its margin. 



Sexual organs. Oogonia. The larger number of these rounded 

 bodies in the case of this species will probably be what are termed 

 oogonia. These are developed in several relations to the hyphae 

 which bear them. They may be terminal, i. e. on the ends of the 

 hyphae which bear them, or on the ends of quite short branches, 

 or intercalary, i. e. when they appear as swellings of the hyphae 

 here and there without any reference to the end. 



A terminal oogonium begins as a slight swelling of the rounded 



