216 SCIENCE PROGRESS 



BOTANY. By E. J. Salisbury, D.Sc, F.L.S., East London College, 

 University, London. 



Morphology. — W. Brotherton and H. H. Bartlett have studied 

 the variation of the size of the epidermal cells from the stems 

 of Phaseolus (American Journal of Botany, April 191 8) in light 

 and darkness. They emphasise the importance of comparing 

 those cells which occupy corresponding positions on the curves 

 of variation. The work of G. Kraus and MacDougal has shown 

 that in etiolated plants the increased length of the internodes 

 is mainly a result of an increase in the length of the cell 

 units, though in part an outcome of their larger number. 

 The present authors find that under constant conditions 

 variation in length of the internodes appears to be associated 

 mainly with an increase in the number of the cells. The 

 effect of light is regarded as directly or indirectly to retard 

 cell division. There is apparently a physiological limit to the 

 size which a primary cell can attain without undergoing divi- 

 sion. In each internode there was an increase in the size of 

 the cells from the base upwards till a maximum was reached 

 followed by a diminution, at the top of the internode, which 

 however was not so great as at the base. 



Miss L. A. Tenopyr (Bull. Torrey Bot. Club, February 191 8) 

 has studied the size and shape of cells in leaves of different 

 forms on the same plant (Campanula rotundifolia and Lobelia 

 erinus) and in closely related species or varieties. In the 

 common Harebell it was found that the broad radical leaves 

 had epidermal cells with an average length of 0*04 mm. and 

 width of 0*039. Those of the linear cauline leaves had an 

 average dimension of 0-034 x 0*032 mm., and transitional 

 leaves 0*038 x 0*034 mm. The results thus agree with those 

 of Sierp, who found that in Mirabilis jalapa, Nigella damascena 

 and Pisum sativum the higher the leaf was situated on the 

 stem the smaller its component cells. Similar results were 

 obtained for Lobelia erinus. A comparison of the epidermal 

 cells from the lobed leaves of the common Chicory with those 

 of an entire-leaved variety showed that the latter were larger 

 but of the same shape. 



Correlation between morphological features of Phaseolus 

 have been investigated by Harris and Avery (Bull. Torrey 

 Bot. Club, March 191 8). Usually three primordial leaves are 

 associated with tricotyledonous seedlings and the latter more 



