366 BOTANICAL GAZETTE [November 



cylindrical resting spores with a flat base and remarkably porous 

 walls, without much content, appear in place of the zoosporangia." 



In the young stages the protoplasm has much the same appear- 

 ance as that of the young sporangia. Fig. 32 represents a section 

 of a developing resting sporangium in which the nuclei are arranged 

 about the periphery. The central mass of granular protoplasm, 

 containing several reserve food bodies, is surrounded by prominent 

 vacuoles. In the mature sporangium the protoplasm forms a 

 definite regularly arranged network in which the nuclei are dis- 

 tributed (fig. 33). There are present, also, deeply staining masses, 

 more or less irregular in shape, which probably represent the fusion 

 of several reserve food bodies. 



On germination the contents of the resting sporangia escape 

 in the form of zoospores not unlike those formed in the zoosporangia. 



to all observations and tests made, it is necessary that the 



germinati 



I have not found any to germinate that were not at least one month 

 old. This applies to cultures developed both in water and on agar. 

 On the transference of the sporangia to fresh water there is no 

 apparent change for some time. After 18-20 hours the two outer 

 walls become cracked open, due very probably to the absorption 

 of water. Sometimes they crack in several places, bringing to view 

 the inner hyaline wall which bears one or more papillae of dehis- 

 cence. In a short time the normal discharge of zoospores takes 



place (fig. 22). 



Nuclear division 



;rical in form i 

 assume to be 



nucleolus. Surrounding this body is a fine granular cytoplasm 

 which can be seen forming an irregular network (fig. 43)- They 

 vary in size from very small, almost invisible dots, to those with a 

 diameter of 6-7 fx. The smaller are found in the actively glowing 

 parts where nuclear division more commonly takes place. The 

 mode of division is rather unusual and suggests a form of amitosis. 

 The first indication of such a nuclear division is a change of the 

 chromatin mass from the more or less normal spherical to an elon- 

 gated form (figs. 48, 52). A transverse line of division is next 



