248 BULLETIN 94. 



diameter of the thread itself. In other cases the thread may de- 

 velop a conidiutn while it is still quite short and the growth of the 

 thread in length practically cease. In other cases the conidia are 

 developed at the ends of the primary or secondary branches as 

 well as at the end of the main hypha. Where the conditions are 

 not favorable for the rapid growth of the vegetative portion of the 

 plant, sometimes the conidia are developed more profusely and 

 rapidly so that they are many times produced in chains. Fre- 

 quently these are in nearly straight chains, or they may form a 

 curve, or again a short and close spiral so that they are held close 

 to the point of origin in a small head. 



The conidium may be spherical or broadly apiculate at the 

 proximal end or more minutely apiculate at the distal end. Some- 

 times there is no enlargement of the fruiting thread at the point 

 of origin of the conidium, but very frequently, and in a majority 

 of cases which I have observed where they are grown in water, 

 there is an oval enlargement of the hypha with a minute apical 

 sterigma which bears the conidium. Where there is quite rapid 

 growth of the fungus the hypha grows onward pushing the re- 

 cently developed conidium to one side but not always freeing it, 

 and soon bears another conidium in like manner. This continues 

 so that several conidia may be borne at short intervals on the 

 same branch, and the successive points of the origin of the conidia 

 are not only marked by the attached conidia but by the oval en- 

 largements on the branch. The appearance is thus in many 

 cases very much like that of the conidiophores of Phytophthora, 

 and deBary has called attention to the same fact. Many of the 

 conidia become free. 



Early in April of the same year cultures were again started on 

 glass slips in water. A preparation was started Tuesday after- 

 noon, April 10, at 3 p. M. At 6 P. M. considerable growth had 

 taken place and several conidia were developed. At 9 P. M. 

 another examination was made and quite a profuse growth was 

 present and numerous conidia or zoosporangia. 



At 9 A. M., Apr. u, there were many free conidia and zoospor- 

 angia and the culture abounded in the form of fructification which 

 so closely resembles Phytophthora. Fresh water was now added 

 to the preparation, a cover glass placed upon it for the purpose of 

 studying it with the high power of the microscope and for obtain- 



