Kingdom: Plantae
Division: Pteridophyta
Class: Pteridopsida
Order: Osmundales
Family: Osmundaceae
Genus: Leptopteris
Species: Leptopteris superba
Common name: Prince of Wales Feather, Crepe fern, Heruheru,  Prince of Wales Fern, Royal fern, Cinnamon fern,

Leptopteris superba is a primitive fern characterised by large fronds (25-100cm x 8-25cm) forming a spreading crown... It has a stout rhizome, sometimes giving rise to a short trunk.  The elliptical fronds are characterised by rich shading and textures.  It is these fronds that taper to each end that make this fern easily recognised.
It has large sporangia that are scattered on the underside of the fronds. 
It is an endemic species rare in Northland and Coromandel but common from Bay and Plenty to Wellington. It is found on Mt Egmont/Taranaki and in the eastern valleys of Taranaki. It is common on the West coast of the South Island. Its habitat is cool shaded wet lowland to montane forests. 

Leptopteris superba Prince of Wales Fern .JPG

A small Leptopteris superba growing North Egmont/Taranaki.
Prince of Wales Fern Leptopteris superba -002.JPG

Leptopteris superba Prince of Wales Fern Heruheru.JPG

Moving the near fronds away to show a short trunk that grows to about 100mm high.
Leptopteris superba Prince of Wales Fern Heruheru-001.JPG

The top surface of a frond
Leptopteris superba Prince of Wales Fern Heruheru-002.JPG

The underside of a frond showing the large scattered sporangia.  
Leptopteris superba Prince of Wales Fern Heruheru-003.JPG

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/