PLANT ORGANS AND ORGANISMS 
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Classification of Buds According to Development. — i. A leaf bud 
is a young shortened shoot bearing a number of small leaves. It is 
capable of elongating into a branch which bears leaves. 
2. A flower bad is a rudimentary shoot bearing one or more 
concealed and unexpanded young flowers. 
5. A mixed bud is a young shoot bearing concealed unexpanded 
leaves and flowers. 
Classification of Buds According to Position on the Stem. — 1. A 
terminal bud is one which is located on the end of a stem (shoot). 
It is capable of elongating into a shoot which bears leaves or both 
leaves and flowers. 
2. An axillary or lateral bud is one which arises in the leaf axil. 
It is capable of giving rise to a side branch or to a flower. Occa- 
sionally axillary buds do not develop and are then called dormant 
buds. 
3. An adventitious bud is one which occurs on some position of the 
stem other than at its apex or in the axil of a leaf. Such buds may 
be seen developing along the veins of a Begonia leaf or along the 
margin of a Bryophyllum leaf after these have been planted in 
moist soil for several days. 
4. An accessory bud is an extra bud which forms in or near the 
leaf axil. 
Classification of Buds According to Their Arrangement on the Stem. 
1. When a single bud is found at each joint or node of a stem, the 
buds are said to be alternate. 
2. When two buds are found at a node they are opposite. 
3. When several buds occur at a node they are whorled. 
THE STEM 
The stem is that part of the plant axis which bears leaves or modi- 
fications of leaves and its branches are usually arranged with mathe- 
matical regularity. 
Stems usually grow toward the light and so are heliotropic. 
The functions of a stem are to bear leaves or branches, connect 
roots with leaves, and conduct sap. 
When the stem rises above ground and is apparent, the plant is 
said to be caulescent. 
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