Epiphytes, lithophytic, rarely terrestrial herbs. Stem erect or pendent, simple or branched, covered in leaf sheaths, pseudobulbs absent. Leaves distichous, flat or undulate, twisted at the base so that the blades all lie in one plane, unequally bilobed, often with a seta in the sinus. Inflorescence terminal, lateral, or both, racemose; floral bracts persistent, often conspicuous and imbricate, occasionally colourful. Flowers resupinate, usually white or greenish, labellum often flushed pink or purple. Lateral sepals adnate to column foot to form a usually obtuse mentum. Labellum shallowly trilobed, with a rounded or concave basal appendage, sometimes extended into small keels; midlobe often with a median keel or callus. Column with a distinct foot; anther cap erect, acute, pollinia six on a solitary, forked caudicle or on two separate ones, viscidium ovate; stigma entire; rostellum erect. (JW).
Species of Appendicula are known to occur from sea level up to 2500 m in a wide range of habitats including mangrove and several types of forests: kerangas, peatswamp, lowland dipterocarp, riparian, and montane. A few species may grow in more open situations such as steep roadside banks and cliffs, e.g. A. alba Blume in Sumatra. (JW).