The xylem
Some plants have woody stems because of where they have originated. Like how if a plant is a first generation hybrid and has in it's genes part of a larger plant, such as a tree, it might have inherited the characteristic of a woody stem from one of it's "parents". This scenario might also work as well if the plant was a second generation. This is also why some plants have skinny or weak stems, like the bamboo tree.
The stems.
stems
stems
stems
Meristematic tissue (vascular cambium) produces secondary growth. In plant stems, this serves to increase the diameter, and it forms between the primary xylem and phloem.
Banana do not grow on trees. Their parent plants are herbs - plants with woody stems and are annuals or semi annuals. The root part of a banana plant is more or less permanent, and from which new stems rise and which then bear fruit.
stem (and leaves) but the part we eat are stems
A flower is one part of a plant, as are roots, stems, leaves, etc.
The shoot is the new plant, the baby. The stem is the woody part of a grown plant.
Because stems, roots and leaves form the main part of the plant body. So long the plant is growing all along these parts, it is the vegetative growth only. When flowering initiates the plant enters in to the reproductive stage.
You can cut down the stems on a potatoes but this may slow their overall growth. The stems are a vital part of the plant which provide nutrients and grow considerably as it does.