MONOBLEPH ARID ALES 8$ 



in some species. According to the observations of Barnes and 

 Melville (1932) on M. polyjnorpha, only 8 minutes was required 

 from the time of contact of the sperm A\ith the oogonial wall 

 until fertilization had been completed and the oospore had been 

 completely extruded from the oogonium. In M. jasciciilata and 

 M. msigjiis the oospores are not extruded but are retained within 

 the oogonium. After fertilization the oospore becomes sur- 

 rounded with a heavy wall, which may be either smooth or bul- 

 late in nature. 



The cytological studies of Laibach (1927) have shown that 

 the oogonium is uninucleate from the time of its formation. 

 After the fusion of Qgg and sperm nuclei, nuclear divisions occur 

 in the oospore during germination, in the course of which meiosis 



probably occurs. 



The generic name Monoblepharopsis was created by Laibach 

 to include two species, M. regignens and M. ovigera, differing 

 from Monoblepharis in the more slender hyphae, proliferating 

 sporangia, and absence of sexual organs. In view of the relative 

 unimportance of these characters, Sparrow (1933) does not ac- 

 cept the genus as valid and would reunite these species with 

 iVIonoblepharis. 



Monoblepharella [Sparrow (1939, 1940)] consists of two 

 species, M. taylori, which was recently found in soil from Trini- 

 dad and other parts of tropical America, and M. viexicana [Shan- 

 or (1942)] from Mexico. Asexually it is similar to Monobleph- 

 aris; the distinctive characters of the genus lie in the behavior 

 of the tgg. When the fertilized tgg is extruded from the oogoni- 

 um, as in certain species of Monoblepharis, it swims away by 

 means of a single cilium derived from the male gamete. 



The similarity of the reproductive structures of Monoblepharis 

 and of the green aka Oedooronium has been stressed in connec- 



^ O c-- 



tion with the views of those who maintain the algal ancestry of 

 fungi. The discoverv^ of such forms as Monoblepharella has 

 tended to discredit this view in favor of the probability of a 

 close relationship of the Monoblepharidales with the Blasto- 

 cladiales and Chytridiales, all of which have uniciliate zoospores. 

 It has been maintained that Monoblepharella and Monoblepharis 

 form an ascending series from an anisogamous ancestor, such as 

 Allomyces javaiiicus. 



