Large and robust with a distinctive tropical appearance, it has fronds up to 5 metres (16 feet +/-) tall that arise from a starchy base that was a traditional food for the Maori.

[3] It is closely related to Ptisana smithii of Vanuatu, Fiji, the Solomon Islands, Samoa and Tonga.

It often grows in New Zealand association with parataniwha (Elatostema rugosum) and supplejack (Ripogonum scandens).

King fern is in serious decline in New Zealand, seriously threatened throughout its range by feral and domestic cattle, wild pigs and goats.

The young fronds are protected as they uncoil by a large ear-shaped basal lobe at the base called a stipule.