Wednesday, September 23, 2020

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Home Issue 26 A touch of light: Ptilotus rising

A touch of light: Ptilotus rising

Ptilotus exaltatus and spider. © Mike Gillam

By MIKE GILLAM

With names like Ptilotus exaltatus or P. notabilis it’s apparent that early Australian plant taxonomists were suitably enamoured of these herbaceous perennials. Ptilotus comes from the Greek ‘ptilotos’ meaning feathery or winged. According to Peter Latz* there are “about 18 species (and many varieties) of these attractive plants…[in Centralia], ten of which are widespread…”

These emblematic native species are also called pussy-tails and foxtails, highlighting our vestigial attachment to feral animals within a slowly changing Australian vocabulary. 

Another name that is gaining ground across the nation, mulla mulla is derived from an unknown Aboriginal language or dialect. Perhaps there’s a reader somewhere who can shed further light on this.

Local Arrernte people know some species of Ptilotus as urreye-urreye. Flowers of various species may be used in ceremonial decorations and Latz describes other points of cultural significance.

I was reacquainted with these winter flowering herbs during a recent walk in the east MacDonnell Ranges. The object of interest for our small group of friends, a deep fissure in the main range with potentially enormous and hopefully unburnt native pines, must wait for a future essay because the Ptilotus palette stole the show.

At first we follow a sandy watercourse with buffel grass still thick and green in places despite the drought. We’re on a national park but weeds don’t observe land title boundaries and buffel is probably revered on the pastoral side of the fence.

As we approach the headwaters, the channel narrows slightly and the buffel looks healthier. A hesitant and interrupted flow of the creek shows in subtle tidemarks; the final resting place for dead leaves and floating debris where surface water was swallowed up by thirsty sand.

Here a germination of river gums embellishes the scene and I lie down to appreciate the crowd of orange red figures standing straight and purposeful amongst the relaxed spray of dark green sedges. The perfectly formed gums stand a mere 50 mm high but already their roots are probably greater than 50 cm deep.

Tussocks of introduced red natal grass indicate favourable micro environments, sediment rich, in the main channel of the sandy creek bed. Higher up and dominating the richer alluvial soils of the creek bank, couch grass (another virulent weed), is thankfully being managed and grazed low by macropods.

As the drainages narrow we make a detour to avoid dense Melaleuca and Witchetty en route to the high country and a deep and steep crevice we’ve seen on Google Earth.

We meander through the foothills, vaguely heading in the right direction and sparing our legs, always choosing the easiest gully and most gently terraced slopes. In the half light of dawn they emerge suddenly from the shadows, a surprising element of haloed softness among the surreal black Sennas twisted in the last inferno.

Now as we trudge with the midday sun at right angles, the Ptilotus appear as exuberant brushstrokes in an otherwise faded and weary landscape. Without discussion each of us make numerous tiny adjustments to avoid trampling their delicate beauty, skirting each patch, crowded drainages and flower filled creases between the rocks.

After savouring foothills awash with various species we encounter one of my favourites, the ethereal green flowering P.macrocephalus ( the photo below, © Mike Gillam, was taken in Tjoritja /the West Macs).

The country opens up like an old friend and our urge to make all speed to our destination in the high country wavers and progress slows. I peer into the depths of flower columns looking for signs of invertebrate life. So much towering biomass, surely there’s something living in there.

Sit for an hour or two and you will see movement, spotted ladybirds, grasshoppers, a tiny wasp; a visiting butterfly catches the attention of a spider sitting patiently among the flower spikes of Ptilotus exaltatus. The spider looks like a fabulous emerald and diamond broach.

Such dense understory shade and cover from above is priceless and I hear a tiny skink pushing through the leaf litter. The orange neck and greenish head of a male Carlia triacantha slowly emerges and looks cautiously in my direction. Very slowly I raise the macro lens and the skink darts away to mock me from the safety of a rock.

Looking me in the eye, he lifts his tail to an angle of about 45 degrees and begins to wave the slender appendage with hypnotic grace and control. These sinuous circular movements are a predator response intent on directing my attention to the skink’s detachable tail. I leave him in peace and look for another that’s less suspicious.

From a broad leafy base, often prostrate on a hot day and semi erect in cooler weather, the flowering stalks of Ptilotus exaltatus rise in a tight bouquet, a floral offering of vivid mauve and white that would lift the spirits of any high street florist.

Not one Ptilotus but tens of thousands of bouquets crown the ridgelines, cloak the hillside flanks and crowd every moisture-holding crease in the eroded landscape.

As we climb the flowering plants continue to surprise and delight us. The geology on all sides is confusing and wild, tipped and buckled, eroded and dissected with ravines. Am I looking at an anticline or syncline or both, I wonder, knowing full well my geologist mates would be appalled by such uncertainty.

We encounter a very steep layer of tilted bare rock with small loose exfoliating sheets that add an element of treachery and focus to our zig-zagging ascent. Progress is slow – walk sideways, search for crevices, bend resistant ankles and mould your feet to maintain contact with the sheer face. Always leaning into the rocks so if you lose your tenuous footing, hopefully you fall against the rocks and have some friction to slow your descent.

Reaching gentler terrain with enough soil to support red flowering Grevillea, Curry wattle and the divine two-toned Acacia melleodora foliage, we pause to study the rocks at our feet. We are surrounded by jumbled plates of ripple stone, evidence of an ancient sea floor tilted and thrust upwards by huge geological movements.

In these circumstances it is customary for European explorers and writers to evoke an ancient inland sea, of rugged coastlines and endless sand ridge deserts appearing as frozen waves. So I can’t resist this nautical moment.

Floating above the sharp clumps of spinifex, a simple plant called wild parsnip, Trachymene glaucifolia catches my eye (below, © Mike Gillam). Curiously domed flowers, intensely structured in neat posies of mauve, ochre and white peeped out at the world. Their close association with the sea floor ripple stone infuses the Trachymene flowers with the character of coral polyps, and the rosettes of Ptilotus leaves, now limp in the midday sun, resemble starfish stranded on an ancient shore.

I recall similar traverses across country full of flowering herbs and shrubs in the days before buffel grass and rosy dock. Of native gardens ever changing, framed by rocks or circles of spinifex, arranged in terraces and revealing endless combinations. Each step a gift as the plant community swayed and danced, sometimes shyly as a Trachymene sprouting from spinifex or bobbing brashly as a ridgeline of Ptilotus.

In the intervening years I watched the march of rosy dock (a native of Afghanistan) as it invaded and mounted the uplands. From sandstone desert mesas to the foothills of the Heavitree quartzite ranges it seemed as though we were watching another chapter in the reductionist story of wild Centralia.

In 2010 I spent a few hours at Chambers Pillar loading my Toyota ute up with hundreds of rosy dock plants heavy with unripe seed that were about to swarm all over the natural monument. It seemed futile, at most I’d achieved a reprieve for a month or two. I felt sorry for the ranger who was trying to hold together a string of similar isolated parks and reserves on a shoe string budget and hoped his or her morale would lift in the knowledge that they were not entirely alone.

Back at our place in town, the rosy dock was set to swarm over Teppa Hill and I sent out an urgent plea to landcare volunteers for help. With eight or ten people we cleared the hill in half a day. That year a total of 770 mm was recorded making 2010 the second wettest on record and only 12.5mm short of the Alice Springs record set in 1974.

That was surely the point. High rainfall in the middle of the year and perfect conditions for rosy dock. With little effort we’ve managed to keep it at bay ever since but we know a significant winter rainfall event could bring it back with a vengeance. Next time we’ll probably modify our approach. Perhaps we’ll remove rosy dock only where it’s in direct competition with existing natives and let the vagaries of climate do the rest.

 

Over the last couple of months, I feel something has changed. So this is not a story of doom and gloom but a mention of the sharp decline of buffel grass and absence of rosy dock post drought and the corresponding renascence of the hillside gardens of Centralia.

 

Certainly the watercourses are still infested by exotic grasses and the danger to old growth trees is acute but much of the high country has reclaimed its true character.

 

For many years Alice residents have watched the relentless march of buffel grass extending up the high flanks of Alhekulyele, the sacred mountain known on maps as Mount Gillen. After rain those bright green flanks bring delight to some and horror to those who know the truth of what is being lost.

 

So too the rosy dock that covers foothills in a lovely but tragic red wash after winter rain. Have these invasive weeds passed their peak for a time at least? Weedy monocultures do often reach a point where they become over burdened by pathogens and ‘pests.’ Certainly in 2020 I’m seeing the leading edge of buffel grass faltering as it steps out of the rich watercourses and attempts to spread up the flanks of adjacent ranges.

 

The drought years of 2018, 2019 have been followed by a mid year 2020 total of just 70 mm. The established buffel tussocks seem to have died in all but the wettest and richest alluvial soils in those locations I’ve visited this year.

 

Sure, one still encounters the occasional buffel tussock that’s germinated in an especially favourable niche but the monoculture, the grey/green plague is retreating. On the colluvial slopes where established tussocks have died, some seed has germinated but this has been sporadic and much of it has failed to persist with the low rainfall so far.

 

There is no invasive rosy dock while the native Ptilotus and many other native plants are enjoying an ascendency on a paltry 70 mm of rain!

 

Aridity is a formidable bastion against alien invaders and that’s one of the reasons I choose to live here. There is a hopeful resilience in this place despite the inaction of governments and the ratcheting industrialisation of agriculture. Perhaps the occasional, not too protracted drought is actually our friend, certainly the friend of biodiversity in the arid rangelands.

 

Over thousands of years our native plant communities have been shaped by low and unpredictable rainfall. Ten thousand years ago during the last pluvial, Aboriginal people made a record in rock petroglyphs of wondrous animals that have since vanished. Many more disappeared in the two hundred years following European settlement.

 

In contrast, there have been no extinctions in the native plant community of the centre according to Latz, although it seems possible that some species vanished before they were scientifically discovered and named.

 

Climate change will bring higher temperatures and likely more rain but it will come harder and faster; potentially more damaging to fragile and erosion prone landscapes. By and large our native plants can survive significant changes to climate but altered fire regimes pose a serious threat unless we are prepared to meet our obligations as curators of this amazing wilderness.

 

I’ll leave the final words to the incomparable zoologist, H. H. Finlayson, author of The Red Centre, a classic book published in 1935, at a critical time in the passing of so many arid zone mammals. He wrote: “The old Australia is passing. The environment which moulded the most remarkable fauna in the world is beset on all sides by influences which are reducing it to a medley of semi-artificial environments, in which the original plan is lost and the final outcome of which no man can predict…”

 

 

 

*Peter Latz, Bushfires and Bushtucker, IAD Press,1995.

 

 

Recently in this series:

 

A touch of light: mistletoe magic

 

A touch of light: Dead finish and friends

 

 

 

1 COMMENT

  1. Thank you so much for this wonderful article. Despite it showing my ignorance, as it had me searching dictionaries and reference materials to get a more in-depth understanding of some parts, these words have given me not just hope for our landscape but a much better appreciation.

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