1913-14.] BOTANICAL SOCIETY OF EDINBURGH 289 



J. trigl u ra is, Linn. ; Ca rex pa u c iflora . Lightf . : C. stell u la to . 

 Good.: ft rigida, Good.: ft. pulla, Good.: Oryptogramme 

 crispa, Br.; Athyriwm flexile, Syme; Lastrea dilo.tata, 

 Presl. var. alpina. 



Athyriv/m flexile, Syme. was found in great quantity 

 and. along with A. alpestre, Miide. was growing in great 

 luxuriance and beauty. 



The members returned home on Friday. 1st August, 

 having spent a short but very pleasant visit in this 

 interesting district. 



Variations in the Growing Region. By Miss Rosa- 

 lind Crosse. B.Sc. (Plates XVIII.. XIX.) Communi- 

 cated by R. A. Robertson, M.A.. B.Sc. 



(Read 11th June 1914.) 



The results embodied in this paper are the outcome of 

 investigations on the growth periodicity of roots and shoots. 

 Last year, when tabulating the results of experiment- 

 the correlation between root and shoot rhythms and calcu- 

 lating the rates of growth, I found that to obtain the 

 growth coefficients for these organs under the various 

 conditions of experimentation it was necessary to know 

 the length of the growing region in each case and to 

 ascertain if it were constant. 



Sachs' measurements showing the region of greatest 

 growth behind the tip of the root of Vicia Faba, are well 

 known. He gives the total growing region as usually 

 10-11 mm., and states that it varies in different roots, 

 and that the transverse zones making up the whole grow- 

 ing region begin to grow slowly, then more and more 

 rapidly, attaining a maximum growth, and then decrease 

 and finally cease altogether. 1 



Whether the growing region varies under different 

 external conditions he does not say. 



As far as I know, no experiments were made by him 

 with the shoots of Vicia Faba, though measurements were 

 made after forty hours on plants in which one or more 

 zones had stopped growing, because in younger plant- 



1 Sachs, ct Lectures," p. 542. 



