STEUCTUBAL BOTANY. 



[71. 



CHAPTER XV. 



THE STEM, OK ASCENDING AXIS. 



211. The general idea of the Axis is this: the cen- 

 tral substantial portion of the plant, bearing the 

 appendages, viz., roots below, and the leaf-organs 

 above. The Ascending Axis is that which originates 

 with the plumule, tends upward in its growth, and 

 expands itself to the influence of the air and the light. 



248, Procumbent stem Chiogenes hispidula. 



212. Although the first direction of the stem's 

 growth is vertical in all plants, there are many in 

 which this direction does not continue, but changes 

 into the oblique or horizontal, either just above the 



249, Decumbent stem Anagallis arvensis. 



surface of the ground, or just beneath it. If the stem 

 continues to arise in the original direction, as it most 

 commonly does, it is said to be erect. If it grow 

 along the ground without rooting, it is said to be pro- 



