BOTANICAL SUBJECTS. 



101 



Fig. 10. Form of ice crystals seen on a shop window on a frosty day, 



of 1891. 



The varieties of forms we now see in seaweeds are either 

 inherited from similarly aggregated cells of primitive times, or 

 have been much modified in their descent by the struggle for 

 life. Be that as it may, we cannot well avoid the inference 

 that the seaweeds of modern times evolved out of more primitive 

 seaweeds ; and that all forms of land plants evolved from sea- 

 weeds. As I said, the protophyta of modern times can endure 

 only in a water medium, or where there must have been much 

 surrounding moisture, and therefore the inference that the 

 original protophyta also were water plants seems legitimate. 



In phasnogams we have to deal with variations of organs, 

 which are evidently formed on one type, as much so as the 

 skeletons of all the vertebrata. How did they originally obtain 

 those forms ? The theory of descent, with modification, which 

 has been accepted by most thinkers, leaves us no alternative. 

 They obtained them by inheritance from anterior forms, being 

 pieces of anterior forms. 



However masked these derived forms of land plants may be^ 

 by modification, accruing from selection in the struggle for life. 



