In some cases, stems also store food. Stems are generally upright and above ground, easy to locate and identify. However, there are many stems that grow below ground or are ground hugging. These stem modifications include corms, bulbs, rhizomes, runners, stolons, tubers and crowns. A modified stem is recognizable because it includes buds and sometimes leaves.
Internodes are the segments of the stem between nodes.
The quality and amount of available light and temperature affect the length of the internode. The distance between nodes can be long or short. This distance reflects growing conditions. Seedlings grown under poor light conditions may be spindly, with very long, thin and weak internodes. The internal tubes in stems act like the plumbing in a house or the blood vessels in people.