EUPHYCOPHYTA 69 



or on an adjacent cell and germinate into a small male plant which 

 is composed of a rhizoidal holdfast with one or two flat antheridia 

 above, though in some cases only one antheridial cell without any 

 rhizoidal portion is formed. Usually two antherozoids are freed 

 from each antheridium into a dehcate vesicle which later dissolves. 



Fig. 36 Oedogonium. A, idioandrosporous nannandrous filament. 

 Bj gynandrosporous nannandrous filament. C, dioecious macran- 

 drous filament. D, monoecious filament. E-H, stages in develop- 

 ment of dwarf male plant ( x 400). I, antherozoid ( x 480). J, escape 

 of zoospore ( x 138). (A-D, after Mainx; E-I, after Ohashi; J, 



after West.) 



The antherozoids are also Uke small zoospores, and if they fail to 

 enter an ovum immediately they may remain motile for as long as 

 thirteen hours. In the macrandrous monoecious species the anther- 

 idia are usually to be found immediately below the oogonia, where 

 they arise by an ordinary vegetative division in which the upper 

 cell subsequently continues to divide rapidly, thus producing 

 a series of from two to forty antheridia. The antheridia frequently 



