31, leaf 1 arises from a node n; leaf 2 is separated from it by an internode m, and is placed to the right or left; while leaf 3 is situated directly above leaf 1.
A single internode of each shoot is swollen to form a pseudobulb.
A, The branch with the leaves numbered in their order, n being the node and m the internode; b is a magnified representation of the branch, showing the points of insertion of the leaves and their spiral arrangement, which is expressed by the fraction or one turn of the spiral for two internodes.
The sheath is often of great length, and generally completely surrounds the culm, forming a firm protection for the internode, the younger basal portion of which, including the zone of growth, remains tender for some time.
Each bundle runs downwards through one internode and then divides into two branches which insert themselves on the alternating bundles entering at this node.
In the cortical tissue beneatJI each furrow a wide intercellular space is present running the length of the internode, and called the (C, D, E from Strasburger's Lehrbuch der Bolanik, by permission of Gustav Fischer.) FIG.
The points on the stem at which leaves appear are called nodes; the part of the stem between the nodes is the internode.