What roles do stems play in lower vascular plants?

In lower vascular plants, the stem serves as a vital structural and physiological axis, performing several key roles:

• Conduction: The stem contains a specialized vascular system—comprising xylem for transporting water and minerals from the roots and phloem for distributing food materials—that connects different parts of the plant.12
• Support: The stem supports the leaves, orienting them to maximize sunlight exposure for photosynthesis. In many lower vascular plants, structural integrity is maintained by strengthening tissues surrounding the vascular bundles, as these plants generally lack the secondary woody growth found in many seed plants.3214
• Growth and Development: The stem is the site of primary growth, which occurs at the apex. It also produces lateral buds and leaves at intervals called nodes.13
• Storage and Protection: Stems may serve as storage organs for food and water. In some ferns, old leaf bases provide a protective "armour" for the stem, and in specialized cases, stems may even house ants.35
• Vegetative Propagation: Many lower vascular plants utilize rhizomes—horizontal, creeping stems—which allow the plant to spread and persist.35