M'S$0URI Botw- 
George Engelmann 
" WEN 
Papers 
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CHAPTER XV. 
THE STEM, OR ASCENDING AXIS. 
211. The general idea of the Axis is this: the central substan¬ 
tial 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. 
212. Although the first direction of the stem’s growth is ver¬ 
tical in kll plants, there are many in which this direction does 
not continue, but changes into the oblique or horizontal, either 
just above the surface of the ground, or just beneath it. If the 
stem continues to arise in the original direction, as it most com¬ 
monly does, it is said to be erect. If it grow along the ground 
without rooting, it is said to be procumbent , prostrate , trailing. 
If it recline upon the ground after having at the base arisen 
somewhat above it, it is decumbent. If it arise obliquely from a 
prostrate base, it is said to be ascending / and if it continue 
buried beneath the soil, it is subterranean. Such stems, although 
buried like roots, may readily be known by their buds as already 
explained (§210). 
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