PAPERS ON BIOLOGY AND AGRICULTURE 183 



REGENERATION IN BRYOPHYLLUM CRENATUM 



Mary E. Renich, Illinois State Normal University. 



Normal 



In Vol. 60 (1915) of the Botanical Gazette, appeared 

 an article by Jacques Loeb entitled "Rules and Mechan- 

 ism of Inhibition and Correlation in the Regeneration of 

 Bryophyllum Calycinum.'' This article was followed by 

 several others from the same author in later numbers 

 of the Gazette, in Science and in the Journal of General 

 Physiology. 



As there was available in the Botany Greenhouse at the 

 University of Illinois a number of plants of Bryophyllum 

 crenatum, the experiments given in Loeb's first article 

 were repeated using this species. While many of the re- 

 sults obtained by Loeb with B. calycinum applied to B. 

 crenatum. several differences were found sufficiently 

 great to warrant noting. Since the plants of B. crena- 

 tum used in the experiments differed from those of Loeb 

 in that they were mature and in flower, the differences 

 were thought at first to be due to maturity or to the 

 physiological state of the respective species. Subse- 

 quently it was found that very young plants of B. crena- 

 tum gave essentially the same results as the mature ones. 

 In the cases where the results with B. crenatum differed 

 from those obtained by Loeb with B. calycinum, the ex- 

 periments were repeated using B. calycinum. 



One difference between the two species should be noted 

 here. TYith B calycinum, whenever growth appeared 

 in the notches of leaves separated from the plants, roots 

 developed before the shoots. The reverse order of devel- 

 opment was always true with B. crenatum. 



Since the study was to be a comparative one, the meth- 

 ods used by Loeb were followed as nearly as possible. 

 The work was done in the greenhouse during the winter 

 months and at a temperature of approximately 70 r F. 

 The numbers used in referring to the leaves correspond 

 to those used by Loeb. 



In the first experiment, 3 leaves of B. calycinum and 

 of B. crenatum were prepared as follows: — leaf 1 was 

 separated entirely from the plant, leaf 2 had a portion of 



