ROOTS : ag 
CHAPTER. {f 
ROOTS 
Growth of Lf 2 Seed is put to germinate in moist air (p. 3), 
Root from the growth of the first root from the radicle may 
Radice. “be observed. The first thing to notice is, that the 
root always grows downwards ; if even the seed is pinned to the 
cork in such a way that the radicle is uppermost, the primary 
root will curve, so as to grow towards the centre of the earth. 
Then when the root is about an 
inch and a half in length, if it is 
marked to its very tip with black 
lines in Indian ink and two milli- 
metres apart, it will be seen at the 
end of twenty-four hours that the 
distances between the lines which 
were at first the same now vary, 
the greatest distance occurring near 
the tip of the root. This shows 
that growth is most active near the 
pes of the root ; the growing | Fie eee GiRMI- 
point is just behind its tip, which — Natine1n Moist AtR, SHow- 
consists of a root-cap, a structure ~" ee eS 
that protects the root as it comes in contact with the soil. 
The portion of the root a little way behind the tip is covered 
with hairs, which are more or less dense according to the 
circumstances under which the root is growing ; if exposed to 
moisture, for instance, they will be more abundant than they 
would be in dry soil. . 
Branches of A primary root soon begins to put forth 
Roots. branches; these always arise laterally, sometimes 
in two rows, sometimes in four, three, or five, or even more. 
They originate within the root, as is clearly shown in the 

