Pneumatophores are the part or extension of the root diverted above the ground level in terrestrial plants, and above water level in aquatic, semi aquatic and in mangroves for aeration and breathing. Generally the roots grows under the ground towards gravity provides support and absorb nutrients for the plants. But this unusual natural phenomenon in some plants that the roots takes a u turn against gravity and appears above the ground or water level to suits its natural habitat by absorbing air from atmosphere and circulating the oxygen to the roots and the plant body.
Such roots can be seen in mangroves aquatic plants and in terrestrial palms varieties. licuala and phoenix are the examples. These roots are aerating roots and should not be confused with aerial or adventitious roots. Aerial roots are gravitropic and grow towards gravity but pnuematophores grows from ground towards atmosphere.
Adventitious roots are the extra roots which emerge from any part of the shoot rather than the root zone. It may emerge from any part of the plants body as from main trunk, branches, nodes and internodes, and from leaves. All adventitious roots are aerial roots till they approach to the ground. In some plants aerial roots converts into the stem once the roots approaches to the ground as in Banian tree and in some other fig species. This natural process of root system helps the plants for its support, for absorbing the nutrients from air and for their natural multiplications.
Adventitious roots are very common in grass family, aroids, pendanus and ficus species. In humid regions during monsoon the adventitious roots are very common in shrubs and trees.