7 6 TEXT-BOOK OF FUNGI 



the oospore commences, separating it from the peripheral 

 periplasm. From this stage of development the conditions 

 differ from those present in Peronospora. The single 

 nucleus divides into two, each daughter-nucleus again 

 divides, making four nuclei in the oospore. The four 

 nuclei then divide into eight, and successive division 

 continues until there are thirty-two nuclei present. By 

 the time this number of nuclei are produced, the exospore 

 and endospore are fully formed and the oospore is mature. 

 The oospore now enters on a resting-stage after having 

 germinated to the extent of what may be regarded as a 

 multinucleate cell or sporophyte containing thirty-two 

 nuclei. 



Wager did not have an opportunity of observing the 

 germination of the oospore, but points out that De Bary 

 states that in germination the oospore becomes a zoo- 

 sporangium, liberating one hundred or more zoospores. 

 From this it is considered probable that if at a later 

 period each of the thirty-two nuclei divided into four, 

 one hundred and twenty-eight nuclei would be present, 

 which would be sufficiently near De Bary's number of 

 zoospores, allowing one nucleus for each. Hence Wager 

 considers that we may regard each of the thirty-two nuclei, 

 together with the protoplasm in connection, as the mother- 

 cell of four zoospores, and the mature oospore with the 

 thirty-two nuclei as the sporophyte. The life-history of 

 Cystopus candidus might then be represented by the 

 following diagram : 



