knee

The term "knee" in botany refers to a rounded or conical outgrowth from the roots of certain swamp-growing trees, such as bald cypress and mangroves. These structures, also known as pneumatophores, grow upward from the root system and protrude above the mud or water. Their primary function is to promote oxygen intake and gas exchange for the submerged roots, which is crucial for respiration in waterlogged environments. Pneumatophores are characterized by small openings called lenticels that allow air to enter and circulate through spongy tissue to the roots.1234