716 AQUATIC PHYCOMYCETES 



with a reticulate or foamy or sometimes homogeneous disposition of 

 the protoplasm; zoosporangia terminal, occurring singly or in fascicles, 

 internally proliferous, varying in shape; zoospores completely formed 

 within the sporangium, escaping upon the deliquescence of sporangial 

 apex, ovoid to cylindrical, posteriorly uniflagellate, possessing an inter- 

 nal organization similar to that of Monoblepharis; sexual reproduction 

 oogamous, male and female gametangia borne terminally in fascicles, 

 internally proliferous, the female bearing up to twenty amoeboid 

 gametes, the male bearing numerous small posteriorly uniflagellate 

 sperms which fertilize the female gametes either outside of or within 

 the oogonium; the zygote propelled by the persistent flagellum of the 

 male gamete, after a period of motility encysting, germination of the 

 thick-walled resting spore unknown. 



Saprophytic primarily on submerged twigs and fruits. 



The main features of Johns and Benjamin's account (1954) of the 

 long-sought sexual stage of this genus are given under the discussion 

 of the order (see "Sexual Reproduction, p. 712). Their work, however, 

 leaves certain questions unanswered, particularly with reference to the 

 sporangial stage. If, as is true of other members of the Monoblephari- 

 dales, the sexual and nonsexual structures are borne on the same thallus, 1 

 what, for example, are the factors that determine which of the stages 

 will be produced? No doubt, as in Monoblepharis and Monoblepharella, 

 temperature plays an important role. In Gonapodya po/ymorpha, R. M. 

 Johns (comm.) says that the sporangia are morphologically distinct and 

 that, although they resemble the female gametangia, they differ from them 

 in the size of the structures produced. Johns further observed that in 

 contrast to unfused male and female gametes the zoospores germinated. 



KEY TO THE SPECIES OF GONAPODYA 



Sporangia and female gametangia long siliquiform, female gametangia 

 usually with one discharge papilla; mycelium divided into distinct 

 segments G. prolifera, p. 7 1 7 



Sporangia long ovoid, female gametangia subspherical to short ovoid, 

 usually with one to four discharge papillae; mycelium obscurely 

 segmented G. polyniorpha, p. 719 



1 Benjamin presents convincing evidence that they do (Myco/ogia, 50: 789. 1958). 



