MONOBLEPH ARID ALES 703 



It can reasonably be supposed that the development of the sporangial 

 plant of Gonapodya and its method of anchorage are essentially similar 

 to those of Monoblepharis. Whether temperature or some other external 

 factor governs gametangial and sporangial formation is at present not 

 known. Further study of these processes, and especially of the origin of 

 the pseudosepta, is greatly needed. In its cytological aspects the spo- 

 rangium of Gonapodya prolifera (Laibach, 1927) resembles that of 

 Monoblepharis. As has been pointed out previously, the type of zoospore 

 and method of formation are also similar to those of Monoblepharis. 



Sexual Reproduction 



The extraordinary type of sexual reproduction found among members 

 of this order has made the group one of greatest interest to the mycolo- 

 gist as well as a never-failing source of stimulation to the student 

 of phylogeny. 



Details of the sexual reproduction of Monoblepharis were accurately 

 portrayed by Cornu, and the observations of the few subsequent 

 workers have added little except cytological data. In such species as 

 Monoblepharis polymorpha, M. faseieulata, M. bul/ata, and M. insignis 

 the antheridia appear at first glance to be inserted on the oogonia (epig- 

 ynous). A study of their development, however, indicates that the 

 oogonium is formed beneath the antheridium and is an intercalary 

 structure. In such a typical epigynous form as M. polymorpha the 

 antheridium originates as a walled-off terminal portion of the hypha, 

 the contents of which are rather homogeneous (Fig. 49 A, p. 704). The 

 more proximal portion of the hypha just beneath the antheridial cross 

 wall then gradually becomes distended and forms a lateral somewhat 

 oblique projection (Fig. 49 B). This lateral distention continues, and a 

 clavate body eventually separated from the hypha by a basal cross wall 

 is formed (Fig. 49 C-D). Often, before the formation of the septa, the 

 antheridium has discharged its antherozoids. The oogonium thus delim- 

 ited gradually becomes more rotund (Fig. 49 D). 



Monoblepharis sphaerica, M. hypogyna, and M. macrandra, though 

 having essentially the same type of sex organs as does M. polymorpha, 

 differ from it in their methods of development. 



