56 



LEMNA. 



[CH. Ill 



(77) Experiments with Lemna. 



Though as above stated water-plants are not generally 

 to be recommended, yet we have found Lemna "useful for 

 purposes of demonstration. They grow rapidly and their 

 increase being principally in one plane is easily noticed 

 at a glance. Moreover a rough numerical estimate of the 





> t • 



w 



Fig. 10. Exp. 77. 



