terminology, a node is the area from which leaves, branch
es, or root
s emerge. Plants are made up of a series of nodes; the areas in between the nodes which consist only of stem are known as internodes. Leafy nodes may consist of one leaf, two leaves, or several leaves. (this is important in identifying the plant.)
In plant propagation, nodes are very important becuase they are the areas where opportunistic roots may form. When a cutting is taken, at least one node must be found in each cutting so the plant can form new roots. (usually at least 2 nodes is better as they are often reluctant to produce leaves and roots from the same node) In other techniques, such as layering, an entire node or series of nodes are buried in dirt or another medium, while the nodes are still connected to the parent plant as well. If things go well, these areas will form new roots, and may be detatched to form a new plant.