Corymbia; ghosts, blood and spots!

This is my first post for a while as we've been exploring the wonders of south-western Queensland, as I mentioned in my last post. We brought back plenty of material for future posts, but for now I'm going to offer something different while I sort out my photos. I also thought this one might be a relatively easy one with which to ease myself back in (my mind is still back with big blue skies, huge horizons, narrow roads stretching out of sight ahead, and surprises round each corner). However, as usually happens in such a situation, it's been a lot more work than I'd realised, as I discovered how much I didn't know and, with new knowledge, came across a couple of misidentifications in my photos. All for the good, I know.

Today I'm talking about an important group of eucalypts, including a few pretty familiar ones, which are no longer called Eucalyptus. That might sound contradictory, but in fact 'eucalypt' is a general name to describe any of the trees that have at some time been called Eucalyptus; they remain as closely related to each other and as instantly recognisable as they ever were.

Flowers of Red Bloodwood Corymbia gummifera, here at Tianjara Falls in Morton
National Park inland from Nowra, south coast NSW. There are a couple of issues here
that are relevant to today's post, the first being the way the flowers are clustered. You may not be
able to see it well here, but the relatively flattened shape of each flower cluster is caused
by the different lengths of the flower stems within the cluster. The lower stems are longer
than the higher ones, so the overall shape is flat, or only slightly domed. This, in botanical
terms, is a corymb, which is different from the way in which other eucalypt flowers grow,
hence the genus name - more on that in a couple of paragraphs time!

The other thing to note in the above caption is the name of the tree. 'gummifera', naturally enough, means 'bearing gum' and while we may not think this remarkable, many early Europeans who encountered eucalypts certainly did. In 1688 the English pirate-naturalist William Dampier reported from the far north-west of Australia that "the Gum distils out of the knots or cracks that are in the bodies of  the trees". Governor Arthur Phillip, who commanded the first British colony on what is now Sydney Harbour, used the term 'gum-tree' in 1778; he collected this gum, and send samples back home, doubtless to have its commercial potential tested. The German botanist Joseph Gaertner first used the name gummifera in a description, but it was Daniel Solander, who sailed with Cook and Banks in 1770 and became the first university-trained botanist to land in Australia, who formally described it in 1788. 

However more than 200 years later the respected botanist Lawrie Johnson of the Royal Botanic Gardens in Sydney, along with colleague Ken Hill, grasped a very large and forbidding nettle indeed when he tackled the problem of what to do about Eucalyptus. The problem, in a gum-nut shell, is that the differences between Eucalyptus and Angophora are no greater than between the various sub-groups of Eucalyptus. Logic demanded either incorporating Angophora into Eucalyptus, or splitting Eucalyptus; Lawrie boldly chose the latter. Before his sad death from cancer in 1997 he had got as far as separating out the bloodwoods, spotted gums and ghost gums as Corymbia; they remain in most books now as the only other non-Eucalyptus eucalypt. There are four sub-groups within Corymbia; in simple terms they are the red bloodwoods (59 species), the yellow bloodwoods (11 species), the ghost gums (24 species) and the spotted gums (3 species). (There are also three outliers, but we won't worry about them today). 

That's about as technical as I'm going to get here - for the rest I'll introduce members of the four main groups and we can just admire them! Many of the bloodwoods, including those most familiar in the south-east, readily 'bleed' sap on the trunk, often encouraged by the gnawing of glider possums.

Desert Bloodwood Corymbia opaca near Windorah, south-west Queensland,
'bleeding' copiously, though not to any detriment! This species was separated
from the much more widespread C. terminalis (see below) in 1985, though
not everyone accepts the distinction.

Many of this group have plated bark, like this one, though not all.

Red Bloodwood again, near Narooma on the NSW south coast.

Pink Bloodwood C. intermedia (like most tree 'colour' names, the pink refers
to the timber, not that I've ever seen it). This one was in the Coffs Harbour Botanic
Gardens on the north coast of NSW, though it is an original tree.

These last two species are trees of the temperate south-east, though a couple of other well-known red bloodwoods are from the south-west (though are not called 'bloodwood').

Red-flowering Gum Corymbia ficifolia, in Wagga Wagga Botanic Gardens.
This small tree has a very small natural distribution in the south-west of Western Australia,
mostly along roadsides, but is very widely planted in gardens and road verges across
southern Australia. This photo shows the corymbs fairly clearly.

Marri C. calophylla, Darling Ranges near Perth. This is a very impressive
tree which dominates some dry forests in the south-west, often along with
Jarrah Eucalyptus marginata. Its big hard fruits (very like those of the Red-flowering Gum
above) are key food for the Red-capped Parrot and the Endangered Baudin's
(or, more helpfully, Long-billed) Black Cockatoo, both of
which extract the tiny seeds with a thin elongated upper mandible.

Others, like the Desert Bloodwood above, are restricted to the arid inland and the seasonally dry north.

Inland, or Desert Bloodwood C. terminalis, above and below. The one above
is in Currawinya NP, in south-west Queensland, and the one below in
Boodjamulla/Lawn Hill NP in monsoonal north-west Queensland,
with torrential summer rains and arid winters.

I'm especially fond of this species, and I see it on any inland trip to the northern half
of Australia, in four of the five mainland states and the Northern Territory.

 Another closely related desert bloodwood was only recognised in 1995.

Sand Dune Bloodwood C. chippendalei, Great Sandy Desert, central eastern WA.
This one only grows on dunes in the central and western deserts.
It was named for George Chippendale, an expert on plants of the Northern
Territory and later the author of the mighty eucalypts volume of the Flora of Australia.
He was also a lovely person who delighted in sharing his knowledge with others.

Corymbia deserticola (another 'Desert Bloodwood' though without a formal English name)
also growing in the Great Sandy Desert. It has a similar distribution to the Sand Dune
Bloodwood, but a wider range of habitats though is usually found on the plains.

Other red bloodwoods grow only in the seasonal tropics.

Small-fruited Bloodwood C. dichromophloia, Boodjamulla/Lawn Hill NP.
This common bloodwood is found from north-west Queensland to the Kimberley.
It is smooth-barked except for the base of the trunk, to which flakes of old bark adhere.

(Another) Red Bloodwood C. erythrophloia, Undara Lava Tubes, north Queensland.
This very striking tree grows in eastern tropical Queensland.

The yellow bloodwoods are much fewer in number. This one is common, and especially conspicuous.

Yellow Jacket C. leichhardtii, Salvator Rosa NP, south-central Queensland
(part of the Carnarvon Range), above and below. This is its southern-most extent,
but it extends north on the western slopes to Mareeba and is readily seen on a
drive through the Queensland tropical woodlands, where sandy soil overlays sandstone.

And one familiar to readers from the Sydney region, is Yellow Bloodwood C. eximia, also found only on sandstone, from Nowra to the Hunter Valley.

Yellow Bloodwood, here at Glenbrook in the Blue Mountains
(and I really must get a better photo of this species!).

There are just three species in the spotted gum group, including the well-known Queensland endemic Lemon-scented Gum C. citriodora - well known because it is widely planted in southern Australia. I used to walk to university in Adelaide through a large stand of them in Botanic Park. However further south by far the best known spotted gum is, wait for it... Spotted Gum C. maculata, which grows all along the NSW coast south from Taree. It is a lovely and readily recognisable tree for its blotchy bark, caused by grey flakes of old bark sticking to the trunk. Here are three Spotted Gum portraits from the south coast of NSW - I'm very partial to them!

Spotted Gum forest along a walk to the beach, Murramarang NP.

Tall old Spotted Gum near Nowra - I couldn't get far enough away to fit
it all into a conventional photo.

Spotted Gum forest with typical understorey of Burrawang cycads,
Macrozamia communis, near Nelligen.

Finally, the last group of Corymbia comprises the wonderful ghost gums, which I blogged about in more detail seven years ago here. By far the best known is the Ghost Gum of central Australia, from eastern WA to western Queensland.

A Ghost Gum C. aparrerinja, estimated to be at least 300 years old, at Trephina Gorge,
eastern Tjoritja (MacDonnell Ranges). For more photos of this very beautiful species,
and some interesting information I was given about the origin of the unusual
species name, see the link immediately above.

Ghost Gum by the road west of Windorah, south-west Queensland.
This must be close to its south-eastern limits.
(It occurs slightly further east to the north of here, at Barcaldine.)

Other ghost gums occur in the tropics.

Rough-leaved Ghost Gum C. aspera, Boodjamulla/Lawn Hill NP. The species is
found across the northern tropics from here in north-west Queensland to the Kimberley.

Ancient C. blakei in Bladensburg NP in central Queensland, growing on
a substrate too hard to penetrate with its roots! It is restricted to this part of Queensland.

Two others in the ghost gum group are very striking trees from eastern Queensland, though to my frustration my photos don't do them justice. Oh well, I'll just have to go back!

Dallachy's Ghost Gum C. dallachiana, Barcaldine. This is a young tree (and drought-affected)
and doesn't give much indication of how handsome it will grow up to be!

And we end with another favourite of mine, the stately Carbeen, or Moreton Bay Ash
C. tessellaris. Heading north we encounter this tall white tree with a rough grey or black
bark stocking in northern NSW, and it continues right up to Cape York.

Well, if this topic didn't interest you much, you won't be still reading! For those who are, thank you for persevering and I hope you learnt something of interest (I certainly have) and at the least enjoyed some of the trees themselves. Next time I'll be back with a more general posting, almost certainly based on one of the lovely parks we've recently spent time in, in south-western Queensland.

NEXT POSTING THURSDAY 8 AUGUST

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The Vanishing Woodland Birds

This somewhat unsettling post is prompted by a truly uplifting event which seems to be still ongoing in Canberra. We are revelling in an influx of Swift Parrots, one of Australia's most threatened bird species.Years go by here without more than a handful of sightings; some years we see none. This is in itself not necessarily a cause for concern as on the mainland they are woodland nomads, following the flowering of the boxes and ironbarks in particular across the countryside. However we know that numbers are perilously low, and falling. 

Swift Parrot Lathamus discolor, Mount Majura, Canberra;
an exquisite little bird which we see all too rarely.

 

The temperate grassy woodlands of south-eastern Australia are one of our most threatened habitats, and were once one of the richest - this is why they were selectively settled early, grazed (and overgrazed), cleared and, worst of all, ploughed. More recently, in places like Canberra, suburban sprawl has chewed up more of the shrinking habitat. (To be fair, recent governments here have made an effort to conserve remaining woodlands and habitats, though the current one seems sadly uninterested. Across the border in much larger New South Wales, the situation is dire.)

Yellow Box Eucalyptus melliodora and Blakely's Red Gum E. blakelyi woodland in the
northern ACT. A woodland is characterised by trees more scattered than in a forest,
so that grasses form a significant part of the understorey.

These two tree species dominate the local woodlands, along with a couple of other species found more to the west of here - the ACT is on the south-eastern edge of the great swathe of woodland that once covered thousands of square kilometres on the western slopes of the Great Dividing Range, from Queensland to South Australia. It has been authoritatively estimated that less than 5% of the original Yellow Box - Red Gum woodland remains, and much of that is unprotected. Remarkably the Mulligans Flat - Goorooyaroo Nature Reserve in the north of the ACT, at just 1600 hectares, is the largest reserve of this habitat in Australia (and thus the world of course). 

 

Blakely's Red Gum, just north of the ACT.

Yellow Box, Campbell Park, Canberra.
One of my favourite tree species!

 

Of the very significant area of this woodland which includes White Box E. albens (not in the ACT) only 0.1% is reliably estimated to be largely intact.

Comparatively, the ACT has done fairly well with woodland reserves over the past couple of decades, but there is little of the necessary connectivity. Fencelines and road verges are cleared or just 'tidied', paddock trees are felled or just eventually just die, firewood collection, overgrazing, overburning and weeds all take their toll and the woodlanders which don't wander are trapped in their little patches. Such small populations will invariably die out in time.

Given this, it is almost inevitable that any species which relies on the habitat to a significant extent will be in trouble and this is what this post is about; a brief introduction to those woodland bird species in this part of the world which are listed as threatened with extinction under either ACT, national or NSW legislation. Recognising a problem, and meeting the victims, is a first step to addressing it. Most of these species, while decreasing, are probably not facing immediate disappearance, though complacency would be very dangerous and sudden population crashes are not uncommon, as we'll see. A few though are in serious trouble, especially two nomads, including the Swift Parrot. 

 

It has other problems in addition to the loss of the woodlands. Uniquely among the woodland specialists, it breeds in tall wet Blue Gum E. globulus forest in south-eastern Tasmania and in autumn crosses the hazardous Bass Strait to winter in the mainland woodland remnants. And those Blue Gum forests are being logged at an alarming rate, mostly on private land. Moreover, and bizarrely, the little Sugar Gliders Petaurus breviceps, which were introduced to Tasmania in about the 1830s, have taken to preying on nests, chicks, and even brooding females in the nest. This was only recently recognised and is a serious problem; for instance it is calculated that 65% of breeding females are killed by Sugar Gliders each year! (It occurs to me that this means that every year most breeding females are likely to be young and inexperienced, but I don't know how much of a problem this is.) Trapping of gliders by means of nest boxes is being trialled. Protection of forests on islands, especially Bruny Island, where gliders are absent, is critical. 

 

Sugar Glider; a seemingly unlikely and hitherto unsuspected assassin.
This one was a long way from Tasmania, in north Queensland.

 

Twenty years ago it was estimated that around 2000 Swift Parrots survived, but numbers were falling then. More recently genetic analysis suggests that the number of breeding birds could be as low as 300 and it is listed, nationally and by the relevant states, as Critically Endangered.

The Canberra influx in the past few weeks has thus been refreshing. Just before the rains came and the flock scattered, there was a count of around 50 birds at Callum Brae Nature Reserve in southern Canberra - in the context of the overall population estimate this is remarkable. Moreover good numbers have been reported elsewhere in Canberra, especially near Mount Majura woodlands. A friend has just told me of half a dozen in suburban Turner, near the Canberra city centre (next to where I lived for 27 years without seeing one!), so there are doubtless more around. We can only cautiously hope that it's a sign that the work being done in Tasmania is paying off. 

Part of a flock of Swift Parrots at Callum Brae a couple of weeks ago, preening in the early
morning sun. I never expected to see this many again, and the number of young birds
among them is heartening.

The other Critically Endangered woodland nomad is the Regent Honeyeater Anthochaera phrygia.  In some ways its plight seems even greater than that of the Swift Parrot, because we don't really know why its numbers have crashed so dramatically compared with other woodland species. Into the 20th century this dramatic bird (which we now know to be a small wattlebird) was present in flocks of hundreds and even thousands from South Australia to southern Queensland. Now there are perhaps 400 left, scattered and wandering from Victoria to northern New South Wales.

[Since I wrote the above I received a comment from regular reader Roman in Canberra, drawing my attention to the book Australian Honeyeaters by the curiously named Brigadier Hugh Officer in 1964, a work I don't own. In it he states “It has stood up successfully to the encroachment of settlement and can still be found in Melbourne’s inner suburbs, while, in Bendigo, it is a bird of city gardens.” So the population crash has been even more sudden - well within my lifetime for instance - than I had appreciated. Roman's full message can be seen in Comments below.]

Regent Honeyeater, Watson, suburban north Canberra, January 2020.
I first saw the species in 1992; in the 29 years from then to now I've seen exactly seven
birds, over five observations. This was the most recent, sadly just a single bird which
stayed for a couple of weeks.

It seems that they require high quality woodland with continuous nectar flow - sadly this scarcely exists any more. Ominously it seems that as the numbers fall the situation spirals; individual birds are easily hounded away by miners and Red Wattlebirds, though Gould commented on their pugnacity when in company. I've also read it suggested that breeding might require a colony, but we really don't know. Targeted tree plantings are numerous and many good people are working to save them. If I may quote myself (from my book Birds in their Habitats, CSIRO 2018): "it’s like watching a medical team fighting a steadily losing battle in the emergency department". Desperately sad in other words, and what can you do for a few hundred birds that wander over thousands of kilometres and disappear for years from a place they seemed to like? I really fear that we may see the Regent become the first Australian mainland extinction since the Paradise Parrot.

How I hope that this was not the last Regent I'll see and, more importantly,
that people will stil be enjoying them long after I've gone.

There are no local woodland birds listed as Endangered (a category between Critically Endangered and Vulnerable) mercifully, but there are seven listed as Vulnerable (ie to extinction, unless the situation changes). One of these is also a nomad, the beautiful and scarce Painted Honeyeater Grantiella picta. Unlike the previous two species however, this one roams across much of inland eastern Australia, following the mistletoe fruiting. However there is also a poorly-understood migration of at least some birds in winter to the north-eastern inland tropics. That is, it is not limited to the box-gum woodlands, and again we don't understand just what's caused its decline though it certainly seems to prefer more intact, less fragmented woodland. I've not seen many, and don't have any good photos; here are a couple of examples! Both were taken in 2013 when a few appeared in flowering mistletoes along the Murrumbidgee Corridor NR near Canberra, and even bred.

Painted Honeyeater in River Oak Casuarina cunninghamiana.
The characteristic yellow wing bar is barely visible here.
The mistletoe Amyema cambadgei, whose foliage mimics that of the Casuarina,
was fruiting heavily here at the time.

Painted Honeyeater on a nest; you're looking at its bill, eye and throat.
I include it here solely because it's so rare to see it.

Two other birds on the list are migrants, so it could be that factors in their winter non-breeding northern range are part of their problem. Superb Parrots Polytelis swainsonii are deserving of their hyperbolic name, simply stunning. They may also be bucking the trend and staging a recovery - or perhaps it's just that having been driven into Canberra suburbia during the 'millenium drought' of the early 2000s they learned that living is easier here and have returned to the city every year since, giving us an inflated idea of their numbers. 

Male Superb Parrot feeding on Acacia baileyana seed pods,
Mulligans Flat NR, northern ACT.

Superb Parrots breed in woodlands in old hollow-bearing trees to the north of the ACT, and many now come into the suburbs for the rest of summer. Then they return to their wintering grounds in the Gwydir and Namoi River catchements of the north-western slopes of NSW. This is cotton country and there is some concern that agricultural chemicals are part of their decline. (There is a separate population, seemingly not migratory, in the Red Gum forests along the rivers of the Riverina in south-western NSW. These birds have been badly affected by logging of the Red Gums, though there is better protection now, especially across the border in Victoria.)

White-winged Trillers Lalage tricolor are more conventional migrants, breeding in the south-eastern woodlands and wintering in the tropical north. It was a bit of a surprise when they were listed as Vulnerable, but those determinations are made by an independent scientific committee and based on substantial data. We should trust the numbers rather than our subjective impressions, and the Canberra Ornithologists Group has built up a very impressive data base of records over the decades.

White-winged Trillers, female above, Barkly Tablelands, Northern Territory,
and male below, Campbell Park woodlands, Canberra.
In the tropics males moult their snappy uniforms and resemble the females.

The other four listed local Vulnerable species are largely sedentary, staying here all year round, though at least one of them moves up and down from the ranges. In their cases loss and isolation of woodland remnants is the only likely cause for their decline. 

Scarlet Robin female Petroica boodang, Narrabundah Hill, Canberra.
This species mostly moves into the lower ranges in summer to breed,
and comes down to woodlands and dry forests around Canberra for the cooler months.

Scarlet Robin male, Black Mountain NR, Canberra.
They really are a stunning little bird, but the local numbers show
a sharp decline in recent years. They don't like suburbia either,
so retreat as the houses advance.

Another local robin is in even more precipitous decline, though it is still doing OK to the west and north-west of here. (That is no reason for complacency though - extinction is the cumulative effect of many populations, like little lights, going out one by one. It is rarely a single cataclysmic event.) Australian Robins were named for the (very superficial) resemblance of the Scarlet Robin to the entirely unrelated European Robin; unfortunately yellow, and even black and white, robins then appeared, but it was too late to change the name then!

Male Hooded Robin Melanodryas cucullata, south of Canberra.
A striking little bird, common across much of inland Australia,
but seemingly disappearing from the ACT. It has gone from most
of its former local strongholds over the past decade or so.

The Brown Treecreeper Climacteris picumnus is in even more trouble here; its future in the ACT seems very limited. I used to be able to find them with some confidence in several ACT woodland sites but not any more. Worryingly it seems to have gone from Mulligans Flat NR, despite a lot of work to enhance habitat (they love a lot of branches and logs on the ground) and even reintroductions from elsewhere. The last good population was in the Glendale Crossing and Old Boboyan Road section of Namadgi National Park in the south of the ACT, but that area was severely burnt in early 2020, and there is no evidence yet that I know of that the species has survived there. It too is still doing well further inland though.

Brown Treecreeper, Newline Quarry site, 2006. This was a good site (though isolated) for them, but
they've been gone from there for some years now.

Varied Sittellas Daphoenositta chrysoptera are found across much of Australia, but in a series of distinctively coloured subspecies. They are the only member of their family in Australia, with another in New Guinea. They are engaging little industrious gleaners of small prey on tree trunks and branches, which they probe with their upturned bills. They are highly sociable. Numbers reported have been dropping steadily as the non-reserved woodlands decline further.

Varied Sittella, Campbell Park, above and below.
This one briefly displayed its glorious distinctive chestnut wing bars.

Showing its strong uptilted bill, clutching lunch.

I am also going to include three species which are resident in the ACT and, while not listed here, are regarded as threatened across the border in NSW. Maybe they really are doing better here, or perhaps the data was insufficient to list them at this stage or maybe there are subtle differences in the criteria between the two jurisdictions. The fact is they are clearly in some sort of trouble, and woodland deterioration is the key factor. My subjective view would be that at least two of them have declined in the ACT in recent times.

Diamond Firetail Stagonopleura guttata, a truly lovely little grass finch which I don't see
nearly as often these days.

Speckled Warbler Pyrrholaemus sagittatus, an attractive little ground dweller
which is not seemingly in too much trouble here, but because of its decline in NSW it
needs to be watched carefully here too. This one was nesting in
the woodland patch behind the Namadgi National Park visitor centre.

Male Flame Robin Petroica phoenicea, high in Namadgi NP. It breeds in banks among
the Snow Gums and spends winter in woodlands around Canberra. Perhaps we're not
seeing much decline here yet, but caution is needed too.

I hope this hasn't been too depressing - I really don't believe that all is lost for most of these birds, but we need to be aware of the situation and to understand it as best we may. And when the Swift Parrots come we must welcome them - for our sakes rather than theirs, as they don't care much about us - and take fresh hope and inspiration from them.

Swift Parrot, Callum Brae NR.
The great ornithologist John Gould in the 1840s described
small flocks of them flying over Hobart ‘chasing each other with the quickness of thought’
(hence the name by which we know it). Maybe it could happen again.

NEXT POSTING THURSDAY 3 JUNE
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Cycads; ancients with an amazing sex life!

Cycads, now a small part of the world's vegetation landscape, once dominated it. Their fossil record goes back unambiguously to 280 million years ago, with ages of over 300 million years often suggested. The younger figure is still 40-50 million years older than the first dinosaurs; this is a truly venerable plant lineage. The first flowering plants, which in time would overwhelm the cycads with a huge diversity of species, didn't appear for another 135 million years (ie 145 million years ago)!

Burrawangs Macrozamia communis, Nelligen, south coast New South Wales. Cycads have long lived in the
metaphorical shadow of flowering plants, as these common NSW coastal cycads do literally, under
the Spotted Gums Corymbia (formerly Eucalyptus) maculata.Like many cycads, the trunk of this species is underground;
no other cycad in the world grows further south than this one.

Now there are now only around 260 cycad species remaining, scattered throughout the world's tropics and subtropics, usually in drier situations (compared with at least 250,000 flowering plant species). Their superficial similarity to palms can be seen in the photo above, and is often remarked upon. It is totally coincidental however, as palms are true flowering plants.

Nonetheless, this Macrozamia riedlei (here in Coomallo Nature Reserve north of Perth) is often known as Zamia Palm
(or just Zamia) for understandable reasons. It is restricted to dry forests, especially Jarrah Eucalyptus marginata, in the
south-west of Western Australia. It was named for Anselme Riedlé, chief gardener (of a team of five)
on the mighty Baudin expedition of 1800-04, who almost certainly collected the first specimen at
King George Sound (now Albany). Sadly he died soon afterwards in Timor, aged just 26.

Cycads arose, as we have noted, in an unimaginably distant past before flowers developed. They reproduce by pollen transfer between cones on separate male and female plants. It was long assumed that this could only be achieved by wind and chance and that only flowering plants utilise animal pollinators, but these notions have now been challenged by detailed observation of several cycad species. It seems undoubtable now that cycads employed insects to efficiently transfer pollen from male to female cone long, long before flowering plants reinvented the trick. One of the first approaches in such studies is to exclude insects, but not wind, from female cones, and vice versa - repeatedly it transpires that pollination can take place without wind, but not without insects, especially beetles and particularly small weevils. We don't normally think of beetles (other perhaps than jewel beetles) as significant pollinators, but in this case it makes sense as beetles were around, with ancestral cycads, well before moths, flies or wasps were.

In some cases beetles have been observed pupating within the males cones, emerging with pollen attached to hairs on their legs and moving to female cones, entering them when they became receptive. Something must be attracting them. Observations on the NSW south coast Burrawang showed that adults and larvae of one species each of both weevils and thrips (a large order of tiny sap-sucking insects) were feeding and breeding in male cones, and later moving to female ones.

Female Burrawang cones, Nowra, New South Wales.
What's going on to strongly attract insects to them?

Studies of other Australian Macrozamia species revealed some remarkable adaptations on the part of the plants (which have had, after all, plenty of time to develop them!). Thrips like cool, dry, dark places and Macrozamia cones usually fit the bill perfectly. However sometimes the cones go to great lengths to expel them. The cones heat to 40 degrees C, and emit water vapour, carbon dioxide and unpleasant terpenes, which causes the thrips to leave en masse; many of them find refuge in nearby female cones and the pollen is transferred.

Some beetles however quite like it hot, and back in the early 1990s work done on the West Indian cycad Zamia pumila showed that in the evening when beetles were active the male cones heated by as much as five degrees, at considerable cost as starch and fat levels in the cone dropped considerably at the same time. The heat also vapourised a chemical with a "sweet minty" scent (in the opinion of the researchers, but the beetles clearly liked it to), and released a sweet secretion, all evidence that the presence of the beetle was worth a lot to the cycad. The beetles were impressed, spending time and even mating in the cone. This study didn't look at the role of the female cones (curiously perhaps) but more recent ones have.

A south-east Queensland study did so and found another version of this fascinating story. Macrozamia lucida is a species from wet eucalypt forests in south-east Queensland, whose male cones harbour large numbers of thrips which eat the pollen but also carry some of it.

Male cones of MacDonnell Ranges Cycad Macrozamia maconnellii, a close relation of M. lucida.

For about four weeks of the year the M. lucida cones produce pollen, and at this time they also go to considerable lengths to expel their thrip tenants. Each morning the cones burn energy to raise their internal temperature by up to 12 degrees! At the same they they emit high levels of beta-myrcene (widely occurring in aromatic plants but also employed in the perfume industry) which has a "harsh, overwhelming odour" (again the researchers' opinion, but again the insects seem to agree). The thrips all flee, carrying pollen with them. And here it gets really interesting because the female cones now emit modest doses of the same chemical, but at lower levels the thrips find it attractive so they seek shelter there - and the plant's job is done! Then the male chemical levels drop again and the thrips return, and the performance is repeated daily until the male cone's reserves are depleted and the female is well-fertilised.

There are just three living families of cycads, and one of them (Stangeriaceae) comprises only three species, one in South Africa and two in Queensland. The largest is Zamiaceae with some 150 species in the tropics and subtropics of the Americas, Australia and Africa (though higher numbers are sometimes cited too). One subfamily of two genera is represented in Australia, and limited to it. There are about 40 species of Macrozamia, and just two of Lepidozamia. Some Macrozamia are common and familiar in their ranges. We've already met a couple but it doesn't hurt to renew our acquaintance.

Burrawang, Nowra, New South Wales.
This forms a near-dominant understorey to the lovely Spotted Gum coastal forests in places.
This is one of several species the seeds of which Indigenous Australians processed via a days-long
complex process of crushing, soaking and heating to denature the virulent toxins. It has always fascinated me
that people would make the assumption that a food which was fatal could be made edible if they
experimented enough - especially in a food-rich environment like the NSW coastal forests.

Macrozamia moorei, here near Springsure in central Queensland, is common in a limited
area of dry ranges inland from Rockhampton to Maryborough. It is probably
the largest of its genus, growing to tree size.

Macrozamia secunda (here in Goobang NP near Parkes, NSW) by contrast is one of the smallest,
with an underground stem and only one to four fronds which mostly grow close to the ground.
Distinctively the pinnae ('leaflets') grow on just one side of the stem.
Its habitat is dry open forests on the hot mid-western slopes of New South Wales.

One of the best-known Australian cycads however has one of the smallest distributions. The MacDonnell Ranges Cycad, introduced earlier, lives only in the dramatic MacDonnell Ranges of central Australia around Alice Springs and the nearby George Gill Range. They are relics of a wetter past, isolated in the relatively sheltered central ranges by the surrounding deserts.

McDonnell Ranges Cycads clinging to the gorge walls in the ranges;
at Ellery Creek Big Hole above, and Standley Chasm below.

The two Lepidozamia are widely separated in distribution, and both restricted. Lepidozamia hopei, reputedly the tallest of all cycads, towering to 20 metres high, lives only in the Queensland Wet Tropics rainforests. L. peroffskyana, far to the south, has a slightly larger range in wet forests on steep slopes from south-east Queensland to north-eastern New South Wales.

Lepidozamia peroffskyana in wet forest on North Brother Mountain, Dooragan NP near Port Macquarie,
north coast New South Wales. Note the huge female cone.
Weevil pollination has been demonstrated for this species too.

The third family is Cycadaceae, which comprises only the genus Cycas, with some 110 species from east Africa and Madagascar to south and south-east Asia through northern Australia to the Pacific. Perhaps 30 of those are Australian; here are three of them. It is a feature of Cycas that the female doesn't form cones, but carry hard spherical seeds on flattened drooping stalks called megasporophylls - in practice these are best considered 'opened-out' cones. They appear in a couple of these photos.

Cycas media is a common cycad in the woodlands of the Top End around Darwin in the Northern Territory.
It is atypical among cycads in being deciduous in the dry season; this plant is producing new growth.
The megasporophylls are obvious.

Cycas media in the understorey of dry monsoon forest south of Darwin.

Cycas calcicola in a burnt landscape at Litchfield National Park south-west of Darwin.
This is a very restricted species, growing only on limestone outcrops near Katherine (hence calciola)
and here on sandstone slopes in Litchfield. Any plant up here must be fire-tolerant.

Lastly Cycas media is a common cycad in drier forests subject to regular burning in east coastal tropical Queensland. Some authorities say that it is also found in the Top End and northern Western Australia, some do not. I'm still trying to fathom this one.

Flourishing Cycas media, Redden Island, Cairns. Both this specimen and the next display megasporophylls.

Cycas media with new growth, Cooktown.

Cycads are old, magnificent, fascinating - and arguably raunchy. I hope you love them too.

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