This article was published in The Fringe, October 2013

Pingao and Spinifex

Last month’s article about coastal plants mentioned both Pingao and Spinifex but did not describe them in any detail. Despite a similar growth habit and ecological niche, they are not closely related. In fact, Pingao is a sedge while Spinifex is a grass, yet they both have much-branched, far-creeping rhizomes or underground stems.

Pingao is the green-orange foliage you can see along many of our beaches on the dunes nearest the sea. In fact, it is the plant that forms the dune. As the wind-blown sand piles up against the foliage, the plant is forced to constantly extend its rhizomes to keep from being buried in sand.

Spinifex has a similar growth habit but is perhaps more frequently found on the slightly more stable dunes. Together the two plants tame our sandy coastlines, controlling the inland movement of sand and to some extent the erosion of sandy shores by wind and sea.

 Pingao was known botanically as Desmoschoenus, but a recent review deems that it belongs in a genus called Ficinia which is predominantly an African family. Its orange foliage is used in weaving tukutuku panels, and the distinctively spiralling flower heads give the plant its specific name ‘spiralis’. The flower spikes are made up of several congested clusters of flowers, with each developing cluster protected by a rigid leaf-like bract. The male and female parts are contained in every individual flower and when mature the entire spike contains many hundreds of tiny black seeds.

Spinifex has silver foliage with distinctly separate male and female plants. The individual sexes can often cover huge areas of a beach, and it is not unusual to find all of one sex dominating an entire beach. The male flowers are erect spikelets producing masses of wind-blown pollen, while the female plants are readily identified with the flower forming the distinctive spiny tumbleweed seen wheeling along the beach later in the season. Each spine contains a single seed at its base, but many are infertile, having not been pollinated. The miracle is how the female manages to collect the wind-blown pollen when the individual sexes are often at opposite ends of the beach, or even on separate beaches.  The tumbling seed-heads of course provide an ideal distribution method and can travel great distances away from the mother plant.

It amuses me how some plant names become common usage. Many native plants are known by the descriptive English name bestowed by early colonials. Consider ‘cabbage tree’ (despite not being related or even looking like a cabbage) and ‘five-finger’ (despite having up to seven leaflets or fingers making up each compound leaf).

For other plants we adopt the Maori name with ease - kauri, nikau and kawakawa, for example. Others become commonly known by their botanical scientific name - Fuchsia, Pittosporum and Clematis - perhaps because they have overseas relatives with the same names.

But how is it that two shoreline plants growing side by side become popularly known by their different names, one Maori and one botanical? In ecological literature they are almost always referred to together, and yet who knows Spinifex as Kowhangatara or Pingao as Desmoschoenus or Ficinia? Perhaps it is because the Pingao is endemic to New Zealand, but Spinifex is also native to Australia where of course it would be incorrect to refer to it as Kowhangatara.