THE GROWTH OF THE AXILLARY SHOOTS 



135 



It may be permitted to mention here briefly some asymmetries 

 in shoot formation in the first and second node apically from the 

 leaf. This phenomenon was most clearly observed in potted 

 stems the apex of which was cut off and which were defoHated, 

 with the exception of one leaf left in the first or second node 

 below the most apical node of the stem (Figs. Ill and 112). 

 When the leaf was in the first below the most apical node, the 

 two leaves of the new shoots growing out in the apical node were 

 no longer identical in size (as they usually are) but the new 



Fig. 111. — Old leaf left at first node below the apical node. The two leaves, 

 1 and 2, of the new shoot in the apical node (which are normally of equal size) 

 show a constant difference, leaf 1 (on the side where the old leaf is) being smaller 

 than leaf 2 (on the opposite side). 



leaflet on that side of the stem where the old leaf was, was always 

 smaller, sometimes completely suppressed. The smaller leaflet 

 is marked 1 and the larger leaflet is marked 2, in Fig. 111. When 

 the old leaf is in the second node below the most apical node, the 

 second pair of leaflets in the new shoot shows this asymmetry 

 (Fig. 112). These asymmetries disappear when the old leaf is so 

 small that the sap sent out by the leaf is negligible compared with 

 the sap in the stem. It is pgssible that these asymmetries are 

 the result of a crossing of the vessels for the ascending sap in a 

 node, whereby the new leaflet on the opposite side from the large 

 leaf receives more sap than the other. 



