In The Hills In The Hills 2016-11

Blechnum novae-zelandiae < Species index > Blechnum vulcanicum

This article was first published in the Tararua Tramper Volume 88, no 10, November 2016

November in the hills with Barbara Mitcalfe and Chris Horne

Blechnum penna-marina, little hard fern; alpine hard fern

We do not know of a Māori name for this fern species, so if you know one, please tell us. Penna is a Latin word for feather, and marina means 'belonging to the sea'. Our fern this month is named after a primitive marine animal, Pennatula, commonly called sea-pen, a slender polyp, shaped just like one of Blechnum penna-marina's stiff, narrow, parallel-sided fronds. Now after that brief, mind-stretching saunter into the animal kingdom, let's get back on the track to plants!

Blechnum penna-marina: Two tall fertile fronds, at different stages of development, arise from a dense bed of green sterile fronds Photo: JEREMY ROLFE

Distribution and habitat

In New Zealand, this dainty but tough little fern is much less common in the North Island than the South Island. Look for it in coastal areas, in light scrub and bush margins, then follow it up into tussock grassland, alpine herbfields, fellfields and shaded outcrops, right up to snowy summits, where it occurs in reduced form at up to 2000 m or to even higher elevations, in the Southern Alps. It also occurs on Stewart, Chatham, Auckland, Campbell and Antipodes islands. Further afield, it is found on Macquarie Island, Australia, South America, and several circum-polar islands.

Rhizome

The black, twig-like, widely-creeping, rhizome sprouts tufts of narrow, erect, parallel-sided, dark green fronds at intervals.

Growth habit

Alpine hard fern carpets the ground with close-growing fronds. The sterile fronds range from 3-25cm long x 0.6-2.5 cm wide, with thin, black-brown stipes (lower stems) of 2–17 cm, scaly at the base. The upper stems (rachises), are yellowish-brown with a strongly grooved midrib. Their 20-40 close-set pairs of narrow, bronze-green, sterile pinnae (segments), are arranged neatly in alternate pairs, with rounded or pointed tips. Their bases are adnate, i.e., attached to the rachis by their own whole width, with no 'stalk'.

The fertile fronds are similar, usually almost twice as tall as the sterile ones, with pairs of even narrower, curved pinnae, much more widely spaced on the rachis. (See image).

Uses

Blechnum penna-marina is a hardy, neat little creeping fern which makes excellent ground-cover for a damp spot. We do not know of any rongoā uses.

During the 1980s, the Levin Horticultural Centre, (Ministry of Agriculture and Fisheries), in collaboration with the DSIR and the NZ Nurserymen's Association, conducted research on numerous NZ plant species, one of which was Blechnum penna-marina. This was because there were extensive, lucrative markets for NZ plants, in Europe, USA and Japan. Scientific evidence of the frost-resistance potential of these plants was critically important, indicative of their ability to survive the severe winters they would experience when they were exported and marketed there as pot-plants or garden plants. (This information was taken from Economic Native Plants of NZ, Brooker, Cambie, Cooper, DSIR, 1988.)

Some Wellington sites

Look for Blechnum penna-marina on Wellington's rugged south-west peninsula, from near the coast, right up to the summits. We have recorded it beside Hawkins Hill Rd, Terawhiti Station (lower Oteranga Valley, and head of Waiariki Valley) and on Long Gully Station. In WCC's Te Kopahou Reserve, it occurs in the lower Waipapa Valley and its true right tributary valley, and in Spooky Gully/Hāpe Stream.

See also

Category

Botany 2016

In The Hills 2016-10 < Index chronological > In The Hills 2016-12