Culm

Culm is a botanical term used to describe the stem of grasses, especially the taller species such as bamboo and rice. The culm forms the main above-ground axis of the plant, supporting leaves and inflorescences. In many grasses it is hollow and segmented by nodes, with the internodes between nodes varying in length.

Anatomy typically includes an outer epidermis with a cuticle, a ground tissue core, and vascular tissue arranged in a ring to transport water, minerals, and photosynthates. Many species have sclerenchyma fibers around the outer region, which adds stiffness. The surface often bears leaf scars where leaves were attached at the nodes.

Growth and development occur from basal meristems. In clump-forming grasses, new culms can arise from tillers, while in bamboos new culms are produced periodically by rhizomes. As culms age, they become more lignified and may change color from green to brown or yellow, increasing rigidity to support taller growth.

Ecology and uses: Culms provide mechanical support and serve as conduits for the plant’s transport systems. They also store nutrients in some species. Economically, culms are important: bamboo culms are widely used in construction, furniture, and crafts, while sugarcane and other crop grasses use their culms to store sugars and other resources. The term is also used in botanical descriptions of grass anatomy and taxonomy.