INFLUENCE OF EXTERNAL CONDITIONS ON GROWTH 



271 





\B 



B 



Fig. 122.— Two branches of broom, Genista anglica. C. 

 grown in dry air; B, in moist air. 



1 I M 



Fig. 121.— Leaves of Tarax- Fig. 123.— Sempervivum. I, normal; II, grown in moist 

 acum. A, grown m very moist air; III, grown in darkness 



atmosphere (actual length about 

 60 cm.). £ and £', grown under 

 usual conditions (actual lengths 

 about 15 and 12 cm., respectively). 



