Special terms used in describing Bamboos

Branch complement: A branch complement may grow at any node on a culm. A branch complement is a cluster of bamboo branches, there will be at most one complement per node. Often complements on different nodes will alternate which side of the culm they grow on.

A young branch complement breaking through the sheath
Branch shoot: Bamboo branches grow from the node much as culms grow from the rhizome, they start life as a shoot. A branch complement will consist of several branches.
Several branch shoots
Culm: A culm is a single stem of a bamboo plant. Normally we think of each stem as being an individual plant, but in bamboo many culms are connected together by underground rhizomes to form one plant, a ramet.
Culm pith: The culm has a hard, almost glassy outer layer, and an inner rather spongy layer. This inner layer is the pith.
Internode: The internode is the section of the culm between two nodes. The part of the culm which is hollow.
Node: Bamboo culms consist of hollow internodes seperated by nodes. The node is the solid circle that closes off the hollow bamboo. It is also the location at which branches leave the culm and where sheaths are attached.
Pseudo-petiole: The pseudo-petiole is the tiny stem that connects the bamboo leaf to the branch.

A bamboo leaf with psuedo-petiole attached.
Ramet: We normally think of each stalk as being a separate plant, but in bamboo many culms will be connected by underground rhizomes and form one individual plant. This individual is called a ramet. The ramet will bloom and die in synchrony.
Rhizome: The rhizome is an underground stem that at first glance can be mistaken for a root. Usually it runs horizontally just under the surface of the earth. True roots grow from its underside, and it will send out shoots from the upper.

a rhizome poking through leaf litter
Sheath: A sheath is a modified leaf which grows around the outside of the culm to protect it. On volohosy the sheaths are very tough, the side toward the culm is as smooth as glass, while the other side is covered with short spines that embed themselves into your hands.
Shoot: A shoot is the start of a new culm. It grows from a rhizome forming a cone which grows taller. Shoots can grow at an amazing pace, 30cm a day is not uncommon. The lower internodes of the shoot grow first, then the upper ones. The basic structure of the adult culm is present in the growing shoot, it starts with almost its adult diameter, and an approximation to the number of nodes it will have when full grown, the internodes are tiny however. A sheath starts at every node and wraps itself around the culm, at the growing tip of the shoot the internodes are so small that sheaths overlap,

A shoot split in half. Note that the internodes get smaller as they near the tip.