THE ROOT. 4} 
about 350 feet in diameter. It had about fifty or sixty stems. 
Another covered a space of about 1700 square yards. On 
the other hand, roots often throw out stems, ascending into 
the air, and becoming independent plants, as the Poplar and 
some Elms, which throw up branches very freely ; and par- 
ticularly those roots called Creeprnc—but in fact subter- 
raneous stems—as the Couch grass. This is a very trouble- 
some plant, difficult to eradicate ; the root creeps horizontally 
under ground, shooting out at intervals herbage which takes 
root, and continuing its subterraneous course, spreads far 
and wide under ground. 
122, The root, then, has three functions to perform,— 
1st, To fix the plant in the soil or to the substance on which 
it grows ; 2dly, To absorb the nutritious matter necessary 
for the growth of the plant ; 3d/y, To discharge noxious or 
useless matters from the plant: This will be referred to un- 
der the Physiology of the Nutritive Organs. 
123. I must here remind the odie of lk able ae ne 
ing of the word “ root,” and this will be best explained by © 
an example: In the bulbous root, when we consider only the 
situation of the part, the root includes both the bulb or bud 
and the fibrous root below it; when we refer only to the 
function, the root is the bundle of small fibres which proceed 
from the lower part of the bulb. Although, in general, it is 
proper to consider as root only the radicles, which imbibe 
nourishment, and although, in many plants, a part which has 
the function of the stem bears improperly the name of root, 
we must still make a distinction between that part of the stem 
which emits no buds and that which does. 
CHAP. Il.—THE STEM (CAULIS). 
“1a. in Steet et veya, pieinesd tyme It : 
‘grows upwards from the neck, gives support to the leaves, 
flowers, and the fruit, and transmits a 
