Rambling (up to 5 m long), epiphytic, occasionally lithophytic herbs. Stem pendent or ascending, sometimes clambering, simple, with a few to many nodes covered by leaf-sheaths. Leaves distichous, linear to oblong, sometimes falcate, usually unequally bilobed or retuse, flat, coriaceous, articulate to a sheathing base. Inflorescences lateral, penetrating the leaf-sheaths, racemose or paniculate, with the flowers clustered in the distal portion of each racemose branch, erect or pendent, many-flowered; peduncle shorter or longer than rachis (or the terminal rachis branch in panicles), glabrous, minutely papillose or distinctly pubescent; rachis with flowers opening from base of inflorescence; floral bracts persistent, triangular, acute to acuminate, erose. Flowers resupinate or not, usually widely opening, rarely scented. Sepals and petals free, similar, spreading. Labellum firmly attached to column, trilobed, shortly spurred, side lobes erect, deltoid or triangular, the back edge of each lobe usually producing a right angle to the front edge, midlobe fleshy, often recurved, usually suborbicular or ovate-triangular; spur bucket-shaped, front wall thicker than back wall, back wall with a projecting erect, rectangular, bifid to subtruncate, ligulate appendage reaching or exserted beyond the entrance to spur. Column erect or slightly recurved, column foot absent; anther cap shortly beaked, pollinia four, arranged as two unequal pairs, waxy, semi-globular, solid, with a long common stipe and a single, usually concave viscidium; rostellum hammer-shaped, bifid after removal of the pollinarium, shorter than diameter of column.
Brandham (1999) and Felix and Guerra (2010) listed a count of 2n = 38 for the genus.
Pomatocalpa is well supported as a member of clade H, within which it is sister to Gastrochilus, a result also found by Topik et al. (2005). A phylogenetic study by Watthana (2007) found that Gastrochilus retrocalla is nested within Pomatocalpa, which was not found here, although bootstrap support for monophyly of Gastrochilus is not strong.
The 13 species of Pomatocalpa are collectively distributed from India and Sri Lanka through Malesia and northern Australia to Fiji, north to northeastern Himalayas and China (Hainan and Taiwan).
All species are epiphytes or lithophytes at 0–750 m in swamp and coastal rocky forests, mangrove and beach forests, and dipterocarp forests.
No uses have been reported for Pomatocalpa; it is occasionally cultivated.
Group 1 (see subtribal treatment in Genera Orchidacearum vol. 6).
Watthana (2007) observed that the flowers seem to fit the beepollination syndrome of van der Pijl & Dodson (1966). In Australia, Jones (1981) observed a small bee (Trigona sp.) with the dark pollinarium of P. macphersonii attached to its head.