No. 495] SYMBIOSIS IN FERN PBOTHALLIA 159 



the hyphae is well shown. The walls, which in the ordi- 

 nary hyphae are moderately thick, stain well with gentian 

 violet, while in the finer granular cytoplasm there are 

 more or less numerous small bodies which stain strongly 

 with safranin and are with little question nuclei. Some 

 of the cells of the host contain unmodified hyphae, which 

 may be so numerous as to fill the cell cavity with a dense 

 coil of filaments. In other cells the hyphae form masses 

 of irregular swollen vesicles with much more delicate 

 walls than the ordi- 

 nary hyphae, and 

 sometimes quite fill- 

 ing the cell. Besides 

 the irregular vesicu- 

 lar swellings of the 

 hyphae described 

 above, there may 

 occur large oval or 

 round structures 

 (Fig. 1) which re- 

 semble the young 



OOgOnia Of Pythium Fi G. 1. A, Cell from the gametophyte of 



or Albugo. These JJ^elX'"^ 



may have a diameter masses f disintegrating starch granules; B, 



of nearly 50 n, but Iar * e conidium (?) of the same, c, fully de- 

 are usually smaller. 

 The nuclei in these 



bodies are more numerous than in the vegetative hyphae, 

 and finally may be very conspicuous (Fig. 1, C). 

 This multiplication of the nuclei resembles the pre- 

 liminaries of zoospore formation in the sporangia of 

 Saprolegnia or Pythium, and occasionally there were 

 seen free in the host cells small bodies that looked as if 

 they might have been discharged from these large oogo- 



itim-like bodi< 



Th( 



