megacarpa is a flowering plant in the mulberry family.

The subspecific epithet comes from the Greek mega ("big") and carpos ("fruit"), with reference to the larger fruits in this subspecies.

The male flowers are minute, occurring in cylindrical inflorescences up to 10 mm long, the female flowers in globular heads 4 mm across, appearing from July to October.

The bright red fruits are 12 mm across.

[1][2] The subspecies is endemic to Australia's subtropical Lord Howe Island in the Tasman Sea, where it is common in lowland forest.