THE AMERICAN BOTANIST 81 



be reprinted in this paper*. These indicate that sections 

 of this plant consisting of 10 nodes represent the mini- 

 mum size at which the activities of the parent organism are 

 duplicated, since it was found that, 



1. Sections of less than 10 nodes rarely produce vegeta- 

 tive buds of roots, except where the apparently localized bud 

 and root forming regions are included in such a section. 

 Such regions were found experimentally to occur approxi- 

 mately at every tenth node. 



2. In pieces of less than ten segments, the advanced 

 state in development of buds and roots resulted in the death 

 of the parent section, presumably due to the withdrawal of 

 nourishment from the stem of the latter. 



Any remaining data concerning Blodea will be brought 

 out later, and it need only be added that the experimental pro- 

 cedure followed with it was the same as will now be described 

 for Ceratophylluni deuicrsiini, L. 



By means of sharp, sterile scissors, the plant body of the 

 latter was divided into 1,2, 3, 4, 5, 6, 7, 8, 9 and 10 segments 

 respectively and grouped as such, care being taken to cut 

 above and below the leaves of each terminal whorl when pos- 

 sible to prevent the possibility of any damage to these. As in 

 Blodea, the terminal bud of each stem was removed as closely 

 as possible to the nearest well defined node, and the rest of the 

 plant used up for cuttings of convenient sizes, according to 

 the conditions of the experiment, before other material was 

 utilized. Large branches were treated similarlv as the main 

 stems. Five cuttings of each were taken, and each cuttmg 

 placed in a stender dish of appropriate size full of pond water. 

 These experiments also extended about a month, and the 



*See Grier, N. M. "Regeneration in Elodea" Anier. Bot. 

 22:55, 1916. 



