Lecture 8, Jiily 19, 1900. 



Transpiration (continued). 

 Peat bog plants . 



Plants witli a pronoiinced Xeropli:"tic structure. 



Sliiiaper says the feature of tlie peat_bos leaf is caused by 

 difficulty of plant to obtain proper laourislunen-t , as water free 

 from acids. Hence even for a plant growing in the water, this 

 kind of water is essential. 



Stall! of Jena, one of the greatest ecologists of the day. 

 Paper on Sleep Movements, dealing with compound leaves. Old 

 meaning of motile leaf was supposed to be the protection against cold. 

 (Darwin.). Stalil shows that warmer climate, greater movement. 

 His view is tliat closing at night is to further transpiration. 

 An expanded leaf would collect dew, while a vertical leaf would 

 shed it. Another point would be the position of the storaata. 



The Legume family is better adapted to its environni;3nt than 

 Other families because it can work at day by protosynthesis, while 

 at night it can collect materials for food. Other plants must do 

 both B.t once. The Legi^me family is best adapted by its stomata 

 and motility to favor transpiration in early morning and ^-ate afternoon 

 Staiil also thinks that the petiole of the poplar is an adaptation 

 along this line. 



The reason that a plant seems to try for a greater transpiration 

 is that the greater the current, the greater aimount of salts carried. 



