60 
PLANT MORPHOLOGY. 
stem from which they arise is spoken of as a node, 
while the intervening portion is called an internode. 
Stem branches normally arise in the axils of the 
leaves, first appearing as little protuberances on the 
stem. Their origin differs from that of the root 
branches, in that they arise as the product of meristems 
developed just beneath the epidermis. The branches, 
like the main stem, manifest negative geotropism, pos- 
sess a growing point at the apex, covered with 
embryonic leaves, and consist of nodes and internodes. 
They may be regarded as a means of developing the 
plant in a lateral direction. 
Buds may he regarded as embryonic stems or 
branches. The bud at the end of a stem or branch is 
known as an apical, or terminal bud; and those situ- 
ated in the axils of the leaves, as axillary buds. 
In some cases they are protected by scales, as in 
hickory, when they are known as scaly buds; while 
buds which are not thus protected, are called naked 
buds. They are further distinguished as leaf, flower, 
and mixed buds, according as they contain or develop 
leaves, or flowers, or both. 
(a) MODIFIED STEMS. 
The stem, like the root, does not always possess the 
typical characteristics given. While most stems attain 
a more or less erect position, there are others which 
bend over to one side, or lie prostrate on the ground, 
and in some cases produce roots from the nodes, as in 
Mentha piperita. 
The stems of a number of plants grow under- 
ground and are known as Rhizomes or root -stocks; 
from the upper portion of the nodes overground 
branches arise, and from the lower surface, roots. 
While most rhizomes are perceptibly thickened, and 
