Kingdom: Plantae
Subkingdom: Tracheophyta
Phylum: Pteridophyta
Class:  Polypodiopsida
Order: Polypodiales
Family: Blechnaceae
Genus: Diploblechnum
Species: D. fraseri
Binomial name: Diploblechnum fraseri   
Synonyms: Blechnum fraseri, Struthiopteris fraseri, Lomaria fraseri, Spicanta fraseri.
Common names: Miniature tree fern, Maukurangi

Diploblechnum fraseri is small indigenous species of fern resembling a miniature tree fern. A mature fern has a short, spindly (>3 cm wide), black trunk up to a metre tall. It has a crown of dark green bipinnate fronds up to 80 cm long by 20 cm wide. The fronds are acutely pointed at the tips. The fronds have distinctive rows of sawtooth projections along the midrib making the frond feel prickly
The sterile and fertile fronds are similar but the fertile fronds tend to be thinner. The minute spores are distributed by wind. Diploblechnum fraseri also spreads by underground rhizomes to form colonies many metres wide.
Blechnum fraseri can be found growing in New Zealand’s North Island and as far as Queenstown in the South Island. It is more common north of Taranaki and in the Northwest of the South Island. It is also found in New Guinea, Indonesia, Taiwan and the Philippines.

A young fern.
Blechnum fraserii-007.JPG

Blechnum fraserii-003.JPG

The underside of a young frond.
Blechnum fraserii-004.JPG

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