pneumatophore
/njuːˈmætəʊfɔː(r)/noun
1
- Zoology the gas-filled float of some colonial coelenterates, such as the Portuguese man-of-war【动】气囊, 浮囊。
2
- Botany (in mangroves and other swamp plants) an aerial root specialized for gaseous exchange【植】（红树林及其他沼泽植物的）出水通气根。