708 



AQUATIC PHYCOMYCETES 



Further cytological work is greatly needed on this and other critical 

 points in the life cycle, particularly of an epigynous species. 



Occasionally one finds smooth-walled endogenous resting structures 

 (Fig. 53 C, p. 730). Whether or not these are always unfertilized eggs 

 which have developed parthenogenetically, as has been suggested by 

 Perrott (1955) and others, awaits confirmation. Lagerheim described 

 the formation of "gemmae" consisting of somewhat rounded chains 

 of hyphal segments in Monoblepharis polymorpha. 



Fig. 50. Sexual reproduction in Monoblepharis polymorpha Cornu 



A-B. Emergence of antherozoid from antheridium. C-D. Antherozoid 

 creeping toward receptive spot of oogonium ; oogonial wall around receptive 

 papilla has begun to dilate. E-F. Antherozoid being engulfed by ooplasm, 

 after which ooplasm retreats into oogonium. G. Antherozoid in motion; note 

 difference in internal structure from that of amoeboid antherozoid. H-J. 

 Emergence of fertilized egg from oogonium; protoplasm of antherozoid may 

 still be distinguished. K. Early stage in formation of bullate wall of oospore. 



(Sparrow, 1933b) 



In Monoblepharella, oogonia and antheridia are frequently formed 

 on somewhat shorter branches of the thallus than are the zoosporangia. 

 The clavate or obpyriform oogonium may, like the sporangium, be at 

 first terminal, but after sympodial branching of the hypha it may appear 



