- Irises grow from thick, underground stems, called rhizomes, that store food produced by the leaves.
- Despite their differing underground structures, corms, tuberous roots, and rhizomes are all referred to as bulbs.
- The plant is tough to stamp out because it develops a system of roots and rhizomes, horizontal underground stems that descend as far as six feet into the sand.
- Mucilages found in rhizomes, roots and seed endosperms may act primarily as energy reserves whereas foliar mucilages appear not to serve as storage carbohydrates.
- In addition, shrub roots and rhizomes grow into above-ground gaps, making below-ground gaps smaller than above-ground gaps.