This article was published in The Fringe, April 2016

Rasp Fern,  Pukupuku

As a name rasp fern does not sound particularly attractive and pukupuku seems to have connotations with fat bellies, yet the beauty of the fern is in the slow spreading blush that it can bring to a dry sunny corner in the garden.

It is a plant that takes its time to achieve substance and make an impact. Plant it today and in perhaps five years it will have established sufficiently to provide a thick dense cover, less than knee-high, as its rhizomes radiate, gradually filling in the corner and producing a glow of pink fronds - hardy, durable fronds that can feel slightly rough or rasping to the touch, but not uncomfortably so. It is the touch of colour that provides Doodia australis the edge over its cousins, Doodia aspera, D. milnei, D. mollis and D. squarrosa. This coloration comes from the flavonoids in the young fronds, providing the pink colour and protecting the tender fronds from ultraviolet radiation. This allows the fern to survive out in full sun where other ferns would shrivel. That's adaptation for you.

Despite a few changes to their names for a variety of reasons, the Doodia species appeared to be closely related and quite distinct from New Zealand's other ferns. They had always been included in the bigger family called Blechnaceae but were widely recognized as being quite distinct. Until recently. Unfortunately, from my nurseryman's perspective, Northern hemisphere botanists decided to rename this southern hemisphere genus into the larger genus of Blechnum. Here it had to be renamed Blechnum parrisiae as a Blechnum australis already existed in Australia.

There is a word to describe the reason for lumping Blechnum and Doodia together, and that is that Blechnaceae is a paraphyletic group including Doodia. I don't profess to understand that, any more than I understand how mammals evolved from reptiles. Perhaps I should just stick to plants, but sometimes I think science ignores the obvious differences in order to adhere to general principles.

New Zealand already has lots of Blechnum species and they are distinctly different from the Doodia species, sufficiently so for me to decide not to move with the times, but to retain the old name of Doodia. The rather strange name Doodia commemorates a London chemist and curator of the Chelsea Apothecaries Botanic Gardens, Samuel Doody. He apparently took a close interest in ferns and felt they deserved to be considered as a separate branch of study from other plants.

You will see Doodia australis growing along coastal slopes where it withstands the onslaught of salt, sun and wind. Its policy is one of 'toughing' out the hard times and seizing the moment when conditions are easier, to grow a few tentative centimetres, always acting defensively to ensure it does not get over-exposed. Its cousins prefer the shelter of scrub lands where Doodia australis also thrives but always growing cautiously to ensure it does not exceed its ability to support itself.