Here are two striking and (I think) attractive Blechnum hard ferns.

Nigrum is Latin for black.  Colenso’s hard fern is named after William Colenso – printer, missionary, politician, and naturalist – altogether a very extraordinary person.  Biography of William Colenso.  The “hard” part of the name comes, I presume, from the texture of the frond; most species are fairly rough and almost leathery.

Both Colenso’s hard fern and the black hard fern are found in wet, shaded, and usually cold habitats.  The above photographs were taken along the Mangahao Makahike Track near Levin.  Although at a relatively low altitude, it nevertheless provides good conditions for these species.

Blechnum is one of the biggest fern genera in New Zealand, with 18 indigenous species.  They are easily recognised because almost all have dimorphic (different looking) fertile and sterile fronds.  The fertile fronds, which make the spores , have much thinner segments and are black or nearly so.  They are also often held up above the sterile fronds.

The following are some of the more common species in New Zealand.