Putative aerial hemi-parasitism or mirrii TinT?

There is a scrub tree here that grows on the floodplains known as Mirrii or leafless cherry/ ballart. Its scientific name is Exocarpus aphyllus and it’s a root parasite on the coolabah mainly, but other eucalypts as well. The Mirrii is used to “make a decoction to treat sores & colds. This plant was also used to make a poultice to rub on the chest for wasting diseases. “Mirri” shrubs are used for smoking for protection (Purcell 2002)” – Bush Tucker, Boomerangs & Bandages  – Michelle McKemey & Harry White – border rivers-gwydir CMA-2011

There are 2 Exocarpus aphyllus living here as TinT guests but I found another recently in a paper titled ” Putative aerial hemi-parasitism ” by Dr Ian Baird. Baird IRC (2014) A novel observation of putative aerial hemiparasitism in Exocarpus aphyllus (Santalaceae). Queensland Naturalist 52, 1-3.

This mirrii TinT is living happily on the banks of Weribone creek between Surat & St George Qld. As the title suggests Dr Baird is explaining this phenomenon of E.aphyllus growing in a coolabah in terms of the individual TinT – without any knowledge or reference to the surrounding landscape. It is located on the highest point of the floodplain on the creek bank which is exactly where the local Aboriginal people would have been located. Every TinT in Nthwest NSW – more than 600 – can be explained individually by normal random distribution methods ( birds animals wind water etc. ) but taken in total & viewed on google earth, natural seed dispersal is not statistically possible. They are clustered around campsites with good surface or underground water or along the old songlines. They are always associated with other CMTs ( ringtrees scarred trees campfire burnt trees etc. )  and/or stone chips & artefacts. Walgett has no natural stone so identifying the older campsites is a no brainer.

The amount of TinTs (accidental epiphytes) here cannot be understood within the bounds of nature. The Exopcarpus TinT is rare but so are these guests – Milgee (Acacia oswaldii)  Leopardwood (Flindersia maculata) Lemon myrtle (psydrax oleifolia) & Belah (Casuarina cristata) of which I have only found 1. The black wattle is common here but Ive never seen it a guest. However there is a black wattle TinT found by Jen Silcock near Mitchell Qld I think – on the banks of the Maranoa. When I read Dr Baird’s paper & he mentioned the mirrii TinT was on the highest part of the flood plain near Weribone Ck, I knew ‘whodunnit’ immediately without knowing that part of Qld at all. In further email contact the very knowledgeable Dr Baird goes on to say “In relation to intentional ‘planting’ of root hemiparasitic species such as Exocarpus aphyllus into a cavity etc of a eucalypt, it would almost certainly need to have been done using a fruit, possibly pretreated to mimic passage through a bird gut. Then the plant would need to very quickly make an haustorial connection to another plant.” 

Its the “pre-treatment” methods we have lost in the years of colonisation & dispersal – most of the commonest guests are hard to germinate from seed. I ran this problem by Stephen Murphy – recreating the country blog and he sent me this practical advice.

“Rosewood ( Alectryon oleifolius ) – I haven’t grown this particular species but have had success with Dodonaea sp. without any seed treatment. Try immersing the seed in very hot water for 30 seconds and cooling rapidly. Neville Bonney in his book ‘from one small seed’ suggests that this works for related species. Peach bush ( Ehretia membranifolia )  – I’ve had no experience with the Peach bush either. The fruit pulp may contain germination inhibitors, so you could try soaking it in water for a few days and removing the pulp when softened but running water through a fine sieve.  Wilga ( Geijera parviflora ) – Neville Bonney suggests washing the seed with water for a few days to remove known chemical inhibitors or nicking the seed coat near the radicle before sowing in Autumn.  Wild orange (Capparis Mitchellii) – a similar process of washing the seed thoroughly to remove the pulp before sowing in early to late winter. Budda ( Eremophila mitchellii ) or any Eremophila really – Peter Barnes from Neds Corner in NW Victoria had a lot of success germinating Eremophilas. He recommended finding the oldest, woodiest nuts under the bush and soak in smoke water for 7 days. The nuts should have cracked and will soon germinate. I assume he would have used a dilute solution of smoke water (1:10) of a product like Regen.” ( More from Stephen later in this blog )

Its hard to look at the Mirrii tree here without noticing it almost always smack UP AGAINST a big old coolabah. The mirrii TinT found by Dr Baird is smack IN the coolabah – see below

Here is another mirrii TinT growing at a warrambool billabong on the neighbours which is the last of the natural water holes to dry out in the area.(below) I think it may have killed it’s coolabah host? The old coolabah ring tree seen here is less than 50 mtrs away & means reliable water – even if you have to dig for in drought. Not far from here is a peach bush camp & massive old scarred trees with a scalded (eroded) red plain that reveals thousands of stone chips.

The 2 photos below are of the most recent mirrii  TinT I found on the songline where the big warrambool meets the big sandhill on another neighbours. This unconventional TinT has the mirrii growing in an open based box tree. This is still a TinT in my books – like the wilga in box & bumble in box growing nearby you see in the other 2 photos below those. This style of TinT is particular to the camps on this neighbouring property. If you look at all 3 TinTs individually you can dismiss them as naturally occurring but not when you view them on google earth. They are along the main road/ Aboriginal path/ songline and clustered around the large sand deposit indicating underground water. Again, many scarred trees, 3 ringtrees & tool working stone chips at this sandy camp.

Here is some more information about Mirrii aka Leafless cherry aka Exocarpus aphyllus –

Exocarpos is a genus of flowering shrubs and small trees in the sandalwood family, Santalaceae. They are found throughout Southeast Asia, Australia and the Pacific Islands. They are semi-parasitic, requiring the roots of a host tree, a trait they share with many other members of the Santalaceae. There is a wide arrange of effects that may occur to a host plant due to the presence of a parasitic plant. Often there is a pattern of stunted growth in hosts especially in hemi-parasitic cases, but may also result in higher mortality rates in host plant species following introduction of larger parasitic plant populations. (Wikipedia)

Personally I havent seen much harm done to the eucalypt host except in the case of rosewood/ boonery guests. Of all the hosts dying of natural causes ( ie not rung or poisoned ) most seem to have been outcompeted by their freeloading rosewood lodgers. That said, there are however, quite a few surprisingly small hosts given their immense age? Probably because as the guest grows it is siphoning off nutrients & water. How the ‘old clever people’ got trees to grow successfully in other trees in this climate is beyond me? Its been around 40 C here the last week (mid march) & Im struggling to keep my conventionally grown garden alive with an electric pump, poly pipe, plenty of mulch and an automatic watering system …

Here is another take on the Exocarpus sp. “The latter are in the mistletoe family but grow in the ground and parasitise on plant roots. Their seed dispersal mechanism requires the bird to pick the fruit off the stem, fly to an adjacent tree, eat the flesh and then wipe it’s beak on a branch, knocking the seed to the ground. This method has an advantage over the eaten seed, as the seed coat does not have to be reinforced to withstand the bird’s stomach. Also the eaten part, the fruit, can be smaller and so can be eaten by a wider range of birds. The disadvantage is in the fact that the seed is dropped to the ground soon after removal from the plant, and would not travel the distances that a seed might if it spent an hour or two inside a bird…..Colour is an important indication to bird dispersal. Red berries are almost certainly dispersed by birds. Spreading the Genes – Peter Vaughan –  (Australian plants – online )

There is more information online about Exocarpus cupressiformis, which lives in higher rainfall country. You might like these 2 snippets: The cherry ballart is a hemi parasitic tree that is seen as a sacred tree “as the little tree has to attach to the big tree … it represents community, in that you’ve got to work together” Julie says. . Aunty Julie is an elder, Indigenous youth advocate, and Harcourt local of the Murnong Mammas.

Propagating the Cherry Ballart has led to many experiments and many failures in nurseries. The mystery of germinating its seed has never been solved. I have even tried feeding the fruit to my chooks, hoping that digestion in a birds gut might do the trick, needless to say I had no success. Could it be the handsome Cherry Ballart, a symbol of cooperation between peoples and caring for the land, is trying to tell us something? Stephen Murphy – recreating the country blog

Yes Stephen, I think they are trying to tell us this:

“ Aboriginal people have interacted with the Australian flora for many thousands of years. It is well to bear in mind that the evolutionary history of many of the species used by them may reflect that interaction.”

Indigenous use of plants in south-eastern Australia – by Beth Gott Honorary Research Fellow, School of Biological Sciences, Monash University

Here is one last interesting TinT you might like – a double with the adjacent tree ‘branded’ with another eagle mark/ Nike tick on the Walgett – Cumborah songline. The twin guests are Currant bush & Rosewood and appear to be a similar age & size – see below

This is the eagle mark weve seen on another rosewood TinT on the songline & on various dead trees including one on Wailwun country.

And this is a photo of the double TinT &  the eagle marked tree showing how close they are together.

Now if you try to tell me there is anything ‘natural’ or ‘coincidental’ about this foursome I would suggest you might need to adjust to the new zeitgeist (German – spirit of the times )

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