This article was published in The Fringe, June 2013
NZ Dock or Runa
The weedy imported plants of the dock family are well known, but the two New Zealand native species, both endemic, are not so well known.
Rumex flexuosus is a widespread species from the Central North Island southwards, but increasingly uncommon. It has been confused with exotic weed forms so it is both out-competed by the weeds, and eradicated as a weed. A typical no-win situation. Only education will teach us the differences and give runa the chance to re-establish across its natural range which used to extend north of Auckland.
Its foliage is an intriguing bronze green colour and the younger rosette leaves are up to 15cm long, while the leaves up the flower stalk are much reduced to less than 5cm as the zig-zag spike extends out to about half-a-metre long.
Its preferred habitat is damp, boggy situations where it can be inundated for months at a time.
The smaller native dock is Rumex neglectus and with a name like that it is not surprising it is not well known. Growing from Cook Strait southwards, it is now only common on the Chathams and Sub-Antarctic Islands. On Enderby Island where stock once grazed it was the dominant plant over large areas, but with the removal of the stock other native plants have recolonized the areas of Rumex. Its foliage is often a bright green but it can become bronzed when solar radiation (insolation) is sufficient to cause the colour change. The leaves are broad and chunky, up to 8cm long, and hug the ground as the stout rootstock spreads sideways forming dense tufts.
As with many of the exotic docks both these plants can be used medicinally and for food, but they are also to be treated with caution as they can be toxic if too much is eaten at one time. Surprisingly, Sir James Hector reported that his crew ate it enthusiastically upon arriving in Dusky Sound in 1863. I guess it made a pleasant change from stale ship's biscuits.
Old museum records of Rumex flexuosus show it grew on Kawau Island, Northland and near Auckland, but no recent records exist. The engineer in charge of the Huia dams, A. D. Mead, records it as local in the Waitakere Ranges, but that is unconfirmed by museum specimens or other records.
Perhaps it cannot be considered truly local but, like so much of our flora and fauna, it needs our help to ensure its survival.