MONOBLEPH ARID ALES 707 



the bullations so characteristic of the oospore of most species of the 

 genus. Lagerheim (1900) states that in Monoblepharis macrandra the 

 zygote may occasionally move away from the oogonium and exhibit 

 amoeboid changes of shape. Rarely the ftagellum of the male persists 

 for a short time, but always for a briefer period than in Monoblepharella 

 and Gonapodya. This behavior has also been noted by Barnes and 

 Melville (1932), although they do not believe as did Lagerheim that 

 fertilization may occur outside the oogonium. Woronin (1904) found 

 the oospore to be composed of two main layers, exospore and endospore. 

 The exospore, in turn, had two parts. Of these the inner, in "A/, sphaer- 

 ica," was thick and colorless and was raised to form the bullations; the 

 outer part was thin, brown, and did not cover the warts. In M. macran- 

 dra, however, the outer, brown layer covered the bullations. Within the 

 exospore the living protoplasm was surrounded by a thin, nearly color- 

 less, elastic wall (endospore). 



In Monoblepharis sphaerica, M.fasciculata, M. insignis, and M. bul- 

 lata, in contrast to all the others in which it is typically exogenous, 

 the zygote remains within the oogonium and becomes converted 

 endogenously into an oospore. 



As Lagerheim and later Laibach (1927) observed, the male and female 

 nuclei in the egg do not fuse at once, but remain side by side (Fig. 49 

 L-O, p. 704) until wall formation has reached an advanced stage and 

 the bullations, if any, are beginning to take shape. Fusion then occurs 

 and the mature oospore is uninucleate (Fig. 49 P-Q). 



Only a few instances of germination of the oospore have been observ- 

 ed. In several oospores which were estimated to be not more than a 

 month old the wall of the spore had cracked open and a single hyphal 

 tube had been produced (Sparrow, 1933b.) Under the existing con- 

 ditions only mycelium was formed (Fig. 53 H, p.730). No other type of 

 germination was reported by Lagerheim or Laibach, nor has it been 

 by Perrott (1955). In Monoblepharis macrandra, according to Laibach, 

 the large resting nucleus of the oospore (Fig. 49 Q, p. 704) may divide 

 into as many as sixteen perceptibly smaller ones. No mitotic figures were 

 apparent. It was supposed that reduction took place during the first 

 division (Fig. 49 R). Upon the formation of the germ tube the nuclei 

 migrated into it, and the vegetative mycelium was established (Fig. 49 S). 



