270 



PART IV. CLASSIFICATION. 



The oospore, which is the product of the fertilisation of an oosphere, 

 germinates without any period of quiescence. It first becomes somewhat 

 pear-shaped ; it is then divided into two by a transverse wall ; the more 

 pointed of the two cells forms the primary root, whilst the other gives 

 rise to the shoot (Fig. 158 d). 



FIG. 157. Section of a female conceptacle, with surrounding tissue, of Fucus tjesicutosus. 

 (x50: after Thuret.) 



FIG. 163. Fucus vesiculosus. a Paraphysis, from male conceptacle, bearing antheridia ; 

 b an oogonium (with paraphyses), showing division of its contents to form eight oospheres ; 

 c process of fertilisation, an extruded oosphere surrounded by spermatozoids; d develop- 

 ing embryo. (x!60: after Thuret.) 



