422 



BOTANY OF THE LIVING PLANT 



through the air. But it shows its real nature on germination by pro- 

 ducing zoospores which are hberated in water. The modification of 



Fio. 357. 

 Fertilisation of thie Peronosporeae. I. Peronospora parasitica, young multi- 

 nucleate oogonium {og), and antheridium {an). 2. Albtigo Candida. Oogonium witli 

 the central, uni-nucleate egg {os) , and the fertiUsing tube (a) of the antheridium which 

 introduces the male nucleus. 3. The same. The fertilised egg (0) surrounded by 

 periplasm ip). (After Wager, x 6G6.) {From Strasburger.) 



such an antheridium as is seen in Vaitcheria into the polHnodium of the 

 Peronosporeae, is acomparativelyshght one: the latter does not hberate 



I'lo. 358. 

 MonobtepJiaris spkaerica. 'End of a filament -vvitii terminal oogonium (o) and an 

 antheridium (a), i, before formation of the gametes. 2, spermalozoids {5} escaping 

 and approaching the opening of the oogonium. 3, osp, ripe zygote and an 

 empty antheridium. (After Cornu. x 800.) (From Strasburger.) 



