Pellacalyx symphiodiscus is a tree in the family Rhizophoraceae. The specific epithet symphiodiscus means 'fused disc', referring to the of the flower.
Pellacalyx symphiodiscus grows up to tall, with a trunk diameter of . The smooth bark is brown. The leaves are oblong to obovate and measure up to long.
Pellacalyx symphiodiscus is endemic to Borneo. Its habitat is dipterocarp forests, to elevations of about .