Medium sized terrestrial. Leaves 4?6, elliptic, to 20 cm long, to 8 cm wide, mottled dark and light green. Flowers solitary, to 8 cm wide; summer. Dorsal sepal ovate, pointed, larger than laterals, white with a greenish centre and purplish veins. Petals oblong, sickle-shaped, slightly longer and narrower than dorsal sepal, slightly twisted, pinkish with purple veins and black warts. Labellum deeply helmet-shaped, purplish.

Indonesia.

P. appletonianum (Gower) Rolfe from the Philippines is a medium sized terrestrial or epilith with mottled leaves, 1 or 2 greenish flowers with purplish suffusions and spots, dorsal sepal slightly wider than petals and a helmet-shaped labellum.

Source: Jeanes, J. (2005). Orchidaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.