    thumbnail|right|200px|european beech with aerial roots in a wet scottish glen. aerial roots are roots above the ground. they are almost always adventitious. they are found in diverse plant species, including epiphytes such as orchids, tropical coastal swamp trees such as mangroves, the resourceful banyan trees, the warm-temperate rainforest rÄtÄ (metrosideros robusta) and pÅhutukawa (m. excelsa) trees of new zealand and vines like common ivy (hedera helix) and poison ivy (toxicodendron radicans). == types of aerial roots == this plant organ that is found in so many diverse plant families has different specializations that suit the plant habitat. in general growth form, they can be technically classed as negatively gravitropic (grows up and away from the ground) or positively gravitropic (grows down toward the ground).ucla botany glossary page - roots === aerial roots as supports === non-parasitic ivy are vines that use their aerial roots to cling to host plants, rocks, or houses. prop roots form on aerial stems and grow down into the soil to brace the plant, e.g. maize and screw pines (pandanus species). === "stranglers" === the banyan tree (ficus sp.) is an example of a strangler fig that begins life as an epiphyte in the crown of another tree. its roots grow down and around the stem of the host, their growth accelerating once the ground has been reached. over time, the roots coalesce to form a pseudotrunk, which may give the appearance that it is strangling the host. another strangler that begins life as an epiphyte is the moreton bay fig (ficus macrophylla) of tropical and subtropical eastern australia, which has powerfully descending aerial roots. in the subtropical to warm-temperate rainforests of northern new zealand, metrosideros robusta, the rÄtÄ tree, sends down aerial roots down several sides of the trunk of the host. from these descending roots, horizontal roots grow out to girdle the trunk and fuse with the descending roots. in some cases the "strangle
Epiphytic_orchids Orchid_morphology Plant_roots