226 Siphonales 



Vegetative propagation is known to occur by detached 'leaves' which 

 grow into new plants, and by the formation of rhizome-like branches from 

 the lower part of the thallus. 



Zoogonidia are unknown. 



Numerous biciliated anisogametes are produced in gametangia, which in 

 Bryopsis are converted 'leaves' but in Pseudobryopsis are ovoid or pear- 



Fig. 146. 1, portion of thallus of Bryopsis cupressoides Lamx. with almost ripe gametangia (<jr), 

 x about 25. 2, pinnae of ' leaflet' of Psendobryopsis myura (J. Ag.) Berth, with gametangia 

 (g) ; 3 and 5 a, copulation of gametes ; 4, zygotes soon after copulation showing chloro- 

 plasts of male (chr") and female (chr') gametes ; 5, zygote in which the chloroplast has 

 divided ; 6, germination of zygote. (From Oltmanns ; 2 and 3, after Berthold.) 



shaped outgrowths from the ' leaves ' (fig. 146 2). Male and female game- 

 tangia may occur on the same axis or they may be on different plants. 

 The female gametes are about three times the size of the male gametes, 

 possessing a rather large posterior chloroplast with one pyrenoid and a 

 pigment-spot. The male gametes, which are of a brownish-red colour, have 

 only a very small chloroplast and no pigment-spot. The paired cilia are in 



