DEVELOPMENT OF PLANTS 



203 



some of its characteristics will reappear in Bryophyta. The 

 gametes themselves, however, show the same range of vari- 

 ations as previously noted. In the simpler types of this genus 

 they are quite alike and on the same plane of differentiation as 



.A 



FIG. 119. Reproduction of Ectocarpus: A, branch bearing several spo- 

 rangia, sp; g, zoospore enlarged. B, branch bearing gametangia, gm. C, the 

 upper motionless gamete (female) surrounded by several still motile gametes 

 (males). D t fusion of the gametes, below the resulting gametospore. 



in Ulothrix, since they sometimes develop as zoospores, directly 

 forming the plant, or they may behave as gametes and fuse to 



