REGENERATION IN ELODEA 



By N. M. Grier. 



T^\ URING the past year, the writer, while observing the 

 "■"^ growing of Elodca (Philotria) canadensis. Mchx. in a 

 laboratory aquarium, was led to note the apparent regularity 

 with which buds and adventitious roots made their appearance 

 upon the plant. Of Gl cases examined, it was observed of 

 the roots that in no case these appeared less than 7 nodes 

 apart, nor more than 13, 11 being most common, and the 

 average number being 10. It was thus apparent that root- 

 forming material was localized. 



This led to speculation as to what portion of the plant 

 would be able to act as a unit organism if judged by the 

 capacity to produce roots and buds when detached from the 

 parent organism. Accordingly, a series of experiments were 

 made in the procedure to be described. By means of sharp, 

 sterile scissors the plant body above the anchoring roots and 

 junction of the branches was divided into 1, 2, 3, 4, 5, 6, 7, 8, 

 9, 10 segments respectively, and grouped as such, care being- 

 taken to cut above and below the leaves of each terminal whorl 

 when possible to prevent the probability of any damage to 

 these. Five cuttings of each were taken, and each placed in 

 a stender dish of appropriate size in water obtained from the 

 same source as that in which the parent plants were growing. 

 The experiments extended about a month, and the results 

 obtained in that time are best presented in the following table : 



