Aerial roots are roots above the ground. They are almost always adventitious

Adventitious

Adventitious has various meanings in various disciplines and in general usage.Adventitious is from the Latin root advenire, meaning "to come or be superadded" and in correct English the meanings tend to have connections to accidental or casual occurrence...

. They are found in diverse plant species, including epiphyte

Epiphyte

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

s such as orchids, tropical coastal swamp trees such as mangrove

Mangrove

Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

s, the resourceful banyan

Banyan

A banyan is a fig that starts its life as an epiphyte when its seeds germinate in the cracks and crevices on a host tree...

 trees, the warm-temperate rainforest rātā (Metrosideros robusta

Metrosideros robusta

Northern rātā , is a huge forest tree endemic to New Zealand. It grows up to 25 m or taller, and usually begins its life as a hemiepiphyte high in the branches of a mature forest tree; over centuries the young tree sends descending and girdling roots down and around the trunk of its host,...

) and pōhutukawa (M. excelsa) trees of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 and vine

Vine

A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

s like Common Ivy (Hedera helix

Hedera helix

Hedera helix is a species of ivy native to most of Europe and western Asia. It is labeled as an invasive species in a number of areas where it has been introduced.-Description:...

) and irritating poison ivy

Poison ivy

Toxicodendron radicans, better known as poison ivy , is a poisonous North American plant that is well known for its production of urushiol, a clear liquid compound found within the sap of the plant that causes an itching rash in most people who touch it...

 (Toxicodendron radicans).
This plant organ that is found in so many diverse plant families has different specializations that suit the plant habitat.