12 THE VEGETATIVE ORGANS 



recognized : (A) a part which grows downwards into the 

 soil, and (B) a part which grows upwards into the air and is 

 green. The former we may call the descending axis or 

 root. This consists of a main tapering root called the 

 tap-root (often distorted in cultivated plants) which gives 

 off numerous branches growing obliquely downwards. 

 These in turn produce branches which are white, and on the 

 younger parts minute root-hairs are developed. The root- 

 hairs are almost too small to be seen with the naked eye, 

 and are generally broken off in digging up the plant. At 

 the end of each root-branch is the growing-point; covered 

 by a protective root-cap. The older root-branches are 

 brown, being covered with a layer of cork, and are unable to 

 absorb water. 



The part of the plant above ground is the ascending 

 axis, and consists of organs of two kinds : (i) a stem 

 which is erect, cylindrical, strong, and somewhat woody 

 below ; more tender, slightly ridged, and green above, with 

 a grey covering of branched hairs. A tender green stem 

 is said to be herbaceous. From this arise (2) thin, flat 

 leaves (Fig. 1,/). In the angle or axil between the leaf 

 and the stem, buds may be found which develop into 

 leafy shoots or axillary branches (b). At the end of the 

 stem and of each branch is the growing-point, protected, 

 not as in the root by a cap, but by the overlapping young 

 leaves of the bud. In older plants the leaves have fallen 

 from the lower part of the stem, leaving scars (s) on the 

 surface. The base or region of attachment of a leaf is 

 somewhat enlarged, and this passes imperceptibly into 

 the blade without a definite leaf -stalk or petiole. The 

 shape of the blade is oblong-lanceolate with an even or 

 entire margin ; and the apex is bluntly pointed or some- 

 times rounded. Like the stem, the leaf is covered with 

 branched hairs. Running through the leaf from base to 

 apex is the midrib, which gives off a branching network of 



