THE SIGNIFICANCE OF THE CAMBIUM IN THE STUDY 

 OF CERTAIN PHYSIOLOGICAL PROBLEMS. 



By I. W. BAILEY. 



{From the Bussey Institution for Research in Applied Biology, Forest Hills, Mass.) 



Plate 1. 

 (Received for publication, January 20, 1920.) 



INTRODUCTION. 



During the last few years, I have had occasion to devote consider- 

 able attention to the study of the cambium of the higher plants, in 

 endeavoring to determine to what extent variations in the structure of 

 timber affect certain of its physical and mechanical properties. In 

 conducting these investigations, I have been impressed by the fact 

 that the cambium is an unusually favorable medium for the study of 

 certain theoretical problems, particularly the working sphere of the 

 nucleus, the much discussed nucleocytoplasmic-relation, and the dy- 

 namics of karyokinesis and cytokinesis. It seems advisable, accord- 

 ingly, to call attention to certain phenomena^ in the cytology of this 

 meristematic tissue which may be of general interest to physiologists 

 as well as to cytologists. 



Description of the Material. 



As is well known, the stems and roots of gymnosperms and dicoty- 

 ledons increase in diameter through the activity of a jacketing layer 

 of undifferentiated tissue which forms xylem internally and phloem 

 externally. In the case of most g5nmnosperms and arborescent and 

 fruticose dicotyledons, the initials of this lateral meristem or cam- 

 bium continue to divide throughout the life of the plant, and their 

 more or less highly differentiated derivative cells constitute the bulk 



^ These phenomena will be described and discussed in detail in a series of 

 papers to be published in the American Journal of Botany. 



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