THE STEM OR SHOOT. 



109 



growth-correlation, and is merely a striking example 

 of a very common phenomenon. 



Harris describes and figures shoots of Gleditschia 

 triacanthos which produced two axillary thorns above 

 the insertion of many of the leaves ; this being due to 

 a second primordium developing below the first one 

 (fig. 30). 



There is described and figured in the 6 Gardeners' 

 Chronicle ' a very rare case in which a tendril of a 



Fig. 30. — Gleditschia triacanthos. Development of second axillary shoot 

 (as 2 ) below the normal one. (After Harris.) Is, leaf-scar. 



passion-flower (Passiflora) produced a lateral shoot in 

 the form of a flower (fig. 31). As the tendril is to 

 be regarded as a modified peduncle or rachis of an 

 inflorescence, this case is a very interesting reversion 

 to the ancestral condition. 



Turning to the Monocotyledons, in a seedling plant 

 of the palm Pinanga metadata, grown in the Royal 

 Gardens, Kew, the plumule was forked down to the 

 extreme base ; the two resulting branches were of 

 equal length and thickness and were subtended by a 

 common basal sheath ; each bore two or three scale- 

 leaves and a terminal foliage-leaf which was forked. 



