1921] JEFFREY & TORREY—HERBACEOUS ANGIOSPERMS 23 
shown an upper slender region of the stem in the sunflower. In 
accordance with the general principles formulated in the other 
examples, the foliar segments are here both outstanding and devoid 
of cambial activity. The remaining bundles are depressed and 
show the presence of secondary growth. 
Fic. 3 
Attention has already been given to the distribution of cambial 
activities in the nodal regions of herbaceous Dicotyledons. Another 
important factor in the development of the herbaceous type is 
shown in text fig. 3, which represents diagrammatically the stems 
of Helianthus annuus and H. orgyalis. In the former more her- 
baceous species a leaf base is represented on the left, at the upper 
end of the figure. This has 3 traces, as is normally the case in the 
genus. In addition to the 3 traces entering at the node, from the 
