S.E. Asia to New Guinea, some Pacific Islands and one species is recorded for Australia. The distichous, strap-like leaves closely enfold the stem at the base.
Some species have terete leaves.
The lateral inflorescence is few to many-flowered. Flowers, often very showy, are medium-sized to fairly large, opening widely. Many species in this genus have been used intensively for hybridizing, resulting in a most stunning array of flower colours, shapes and sizes. The species in this genus freely interbreed with species of other closely related genera such as Aerides, Arachnis, Ascocentrum, Renanthera, Phalaenopsis etc. Six sections have been created for this genus.