Emu dung and the nodding geebung

Snottygobble sounds like a name for a very silly plant indeed.

But that first impression doesn't convey the ecological importance of this genus of shrubs, otherwise known as geebung or by their scientific name, Persoonia.

The bushes in the Persoonia family reach around two metres in height and can be heavily laden with fruit. That's unusual for plants living in an otherwise resource-scarce environment.

This leads biologists to believe the endemic plants play a crucial role as a food source for other organisms, such as possums and emus.

It is likely that at some point you've walked past one of these plants, as there are almost 100 Persoonia species across the continent.

It's unlikely, though, that you've seen the nodding geebung (Persoonia nutans), an endangered species with delicate leaves of lime green and stems of red.

It gets the 'nodding' name from the style of fruit, which is droopy and darkens to dark purple as it ripens.

The Australian Plantbank has an ongoing project on Eastern Australian persoonias that could lead to some critical conservation outcomes.

Plantbank researcher Katharine Catelotti says success with the genus is 'one of the holy grails of horticultural research'.

'They haven't really got backups,' she says of the nodding geebung.

Catelotti's theory is that the seeds of the nodding geebung might need to be picked out of emu poo to be viable: the horticultural holy grail has to go through poop.

At first it sounds bizarre—why would you feed the precious seed of an endangered plant to Australia's largest bird?—but on closer inspection, the emu hypothesis shows some incredible biological processes that might be key to the snottygobble's survival.

Professional plant scientists and amateur horticulturalists across Australia have been trying to germinate Persoonia seeds for years, as of the time of recording, no one has managed to find the exact catalyst that the seeds need to rouse them from dormancy.

They are searching for the 'magic key'.

The processes that the plant scientists put the seeds through read like a checklist for an introductory course on torture: drowning the seed, heat shock to simulate bushfire, bending time through long-term temperature control, and feeding the precious seeds to emus to see if the mystery lynchpin for germination is within an emu's guts.

If it is, it could explain why the drooping fruit of the nodding geebung are so plentiful, and perfect in size for the dexterous emu's beak to pick out of the undergrowth.

'That the plant would bother to put energy into creating all of that [fruit] means that part of the evolution has been to be eaten by animals; that's a dispersal mechanism,' says Catelotti.

'There's research which shows that emus are important for dispersing the persoonias.

'There may also be importance in the digestion of the seed, because the next level under the fruiting structure is an endocarp, which is a hard woody casing. It's a very protective covering. That indicates that it's protecting the seed from some physical process.'

That physical process could be in the digestive tract of the emu, as the birds eat small rocks to aid with digestion of fibrous vegetation.

As the seed passes through the system, it might get scarified, or perhaps even coated in a chemical that is an important signal for germination.

Or the emu's gut might provide a microbe from its flora that aids the plant when it hits the ground.

But then again, it might be something entirely different, says Catelotti, who is also testing the seeds with chemical elements of smoke, and plain old manual cracking of the seed casing.  

'Scientists just do not know,' she says.

'That's the main obstacle. There are a lot of things to take into account when working with endangered species—but I guess that's the point: with science you've got to take a few risks.'

Find out how to make a reticent adolescent emu eat endangered seeds (for science!) by subscribing to Off Track on iTunes, ABC Radio or your favourite podcasting app.