lit 



ERIMEUTS WITH JOL^US. 



In most of the experiments here reported the 

 plant used was Coleus blumei , this species .being selected 

 because of the ease with which it can be grown under 

 glass at any season and also because its soft and fleshy- 

 stem of nearly square cross-section makes it particular- 

 ly suitable for developing and testing a technique of 

 sealing which may be expected to be widely applicable to 

 other species. In various experiments four strains «*<>/*• 

 sub-varieties of Joleus were used, these differing in 

 color, leaf form, and the like, as is characteristic 

 of this species. Results with all four strains were 

 essentially alike and have been repeatedly obtained in 

 three successive seasons, from 1915 to 1917. 2he be- 

 havior of CJoleus on the exclusion of osygen from the roots, 

 according to the method described in the last chapter , 

 is typified by the following history of plant number 

 209. 



