Cypress knee

Respiratory knee or knee roots are trained by some marsh and mangrove trees. They break through the root loops or negative - gravitropic ( in the opposite direction of gravity growing ) excesses of horizontally oriented, near-surface underground root system, the soil surface. Respiratory knee serve as pneumatophores; their aerenchyma ( aerenchyma ) ensures the gas exchange of the underground root system in the oxygen- poor sediment.

Taxa with breathing knees:

• Upright cypress, China cypress, bald cypress: cypress family
• Bruguiera, Ceriops: Rhizophoragewächse
• Xylocarpus: Mahogany plants