324 Agricultural Experiment Station, Ithaca, N. Y 



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within a single cell of the prothallium, sometimes completely fillin 

 even quite large cells, while at other times the body may be smaller 

 especially in smaller cells of the prothallium, where it sometimes 

 consists of only a few hyphal branches closely curved upon their 

 parent cells. These liyphal branches vary from 7/y to 15// in 

 diameter or may even be of a greater diameter, and are one and 

 one-half to two times longer. When the plant body in a single 

 cell becomes mature it may spread to the surrounding cells by 

 certain of the external hyphal branches putting out a slender germ 

 tube which pierces the adjacent intervening wall. This is done by 

 the tube of the hypha excreting a substance which dissolves the 

 cellulose of the wall making a small minute pore and at the same 

 time turning the adjacent portions of the wall brown in color. The 

 wall of the slender thread which squeezes its way through thia 

 opening is also colored brown, and this color is frequently extended 

 to the slender portion of the thread or tube, in which the proto- 

 plasm passes or migrates to the center of the cell as shown in Fig. 44. 

 When it has reached the center of the cell lumen the free end 

 enlarges and forms a rotund body which finally becomes oval. At 

 this time it is about 15// to 25// in diameter, with quite coarsely 

 granular protoplasm and with one or more large vacuoles. By this 

 time also all of the protoplasm from the original cell has moved 

 into this oval body in the center of the cell, leaving behind only the 

 wall of the slender tube by which it gained entrance and which is 

 still connected with the wall of the living organism. This old wall, 

 as well as the wall of the prothallial cell where the organism entered, 

 becomes brown in color soon after the protoplasm has passed 

 through into the center of the cell of the host. From the free and 

 smaller end of this oval cell a short protuberance grows curving to 

 one side usually rather close to the side of the parent cell. Some- 

 times this branches quite soon in a dichotomous manner and the 

 two short cells curve in opposite directions. If dichotomy does not 

 occur at the beginning of the protuberance another branch arises 

 soon from the original cell or from the branch. These protuber- 

 ances become enlarged at a very short distance from their origin 

 forming oval cells. These in like manner produce short branches, 

 and the process continues until a botryose or convoluted mass of 

 cells is developed which eventually fills the cell of the prothallium, 

 and the elements of the botryoid body become angular from mutual 



