308 Agricultural Experiment Station, Ithaca, N. Y. 



teased out directly in the bottom vessel of the Tetrie 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 pi-eparation 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 constrictions of 

 the hyphae corresponding to those where they pass through the cell 

 walls of the host. The branching is in an alternate 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 num.ber 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 

 •end of a hypha or short branch, which continues until the spherical 

 body is about 18//-25// in diameter. During its growth in size the 

 protoplasm which fills the interior is supplied by the supporting 

 hypha or oogoniophore, without, however, emptying any portion 

 of the latter stnicture. When the oogonium has reached its full 

 size, a septum, or partition wall, is formed cutting off its protoplasm 

 from that of the stalk or oogoniophore. At this time the wall of 

 the oogonium is thin and the protoplasm finely granular, though 

 distinctly so, and completely tills the interior of the oogonium. The 

 wall now increases somewhat in thickness, but remains colorless. 



The egg cell of the oogonium is now soon differentiated, and 

 in most cases, except where parthenogenisis takes place, is probably 

 influenced by the development of the antheridium. The finely 

 granulated protoplasm of the oogonium becomes coarser and is 

 gradually collected iuto numerous small irregularly rounded masses. 

 At the same time all of the coarsely granular protoplasm contracts 

 from the wall of the oogonium and moves toward the center forming 

 there a rounded central mass somewhat less in diameter than that of 



