Blechnum chambersii
Found throughout New Zealand.
The fertile fronds are the fine fronds coming from the centre of this fern.
Blechnum fluviatile
Found throughout the country.
The fertile fronds are usually quite upright.
Blechnum fraseri
This species looks like a small tree fern. The fertile fronds look similar to the sterile fronds although the pinnae become narrower.
The young developing frond in this image will become a fertile frond.
Blechnum penna-marina
Common in the South Island and lower North island, especially in alpine areas. Found in localised areas in the upper North Island.
Blechnum membranaceum
This species is similar to B. chambersii but it has smaller sterile fronds and the fertile fronds are longer than the sterile. The sterile fronds form a flattish rosette with the fertile fronds being more upright.
Blechnum novae-zelandiae
Found throughout the country especially on banks.
Blechnum procerum
Common throughout the country, though mainly at higher altitudes in the North Island.
Blechnum parrisiae
This species was known as Doodia australis until recent years.
This species is characterised by its distinct pink colouration and harsh foliage.
It does not have separate fertile fronds. Instead, the sori (spore-bearing structures) are on the underside of the fronds in rows parallel to the mid-rib as shown in the image below.
On the ground the fronds remain in the juvenile form, but once a certain height is reached on the host tree, the foliage changes into the adult form.
This image shows on the left a sterile frond, in the middle a young fertile frond, and on the right a mature fertile frond.
Blechnum filiforme
This Blechnum fern is unusual in that it has distinct juvenile and adult forms and is a climber.
You can see some juvenile fronds in the lower left of this image where the fronds are smaller and the pinnae ("leaves") are much shorter than the adult sterile fronds which are in the right-hand side of the photo.
The thin dark fronds are the fertile fronds.
Blechnum discolor
Found throughout New Zealand.
Blechnaceae
This family are characterised by many of the species having sterile and fertile fronds that differ in appearance. The pinnate fronds are often pinkish when young.
