Should we ban Cunjevoi?

 Alocasia brisbanensis

Yesterday a petition was lodged with the Queensland Parliament, to ban this plant. 

https://www.parliament.qld.gov.au/Work-of-the-Assembly/Petitions/Petition-Details?id=4006

The wording of the ban requests:  the total ban of the sale, keeping, growing or removing from our rainforests Cunjevoi or Alocasia brisbanensis, Alocasia macrorrhizos plants across the state.

Cunjevoi is a well-known plant to all those who walk in the rainforests of Queensland and New South Wales. The juice of the leaves is often recommended as a cure for the sting of the giant stinging tree.

 

It is also often grown in gardens, and public parks, because it is beautiful. I see on the internet that Bunnings offers it for sale. 

The petition states: "It has been found that even a small snippet of the plant could kill an adult, child or pet in under 30 minutes." It also claims that even whippersnipping near the plants has dire effects on the person wielding the tool.

These claims are obviously overstated, but is cunjevoi really dangerous?

Yes. The book "Australia's poisonous plants, fungi and Cyanobacteria", by Ross Mckenzie, CSIRO Publishing, 2012, is one of the best guides to poisonous plants in Australia. 

It awards Cunjevoi 1 (one) star for degree of danger.

But is it really THAT dangerous? To put it in proportion, compare it with Narcissus (daffodils and jonquils), which rate 2 stars for degree of danger. Logic suggests that an even smaller "snippet" of daffodil must have the deadly effect described above.

SO SHOULD WE BAN DAFFODILS?

Well yes, if we are to be consistent, we should be regarding this as a more urgent matter than banning Cunjevoi. All Narcissus (daffodils and jonquils) rate 3 stars for weight of evidence of toxicity, and 2 stars for degree of danger.

In fact, if we wanted to get the job done properly, we should comb through that CSIRO book, and get a lot of plants banned. There are more than seven thousand of them that qualify for one star or more. If we follow the logic of banning Cunjevoi, they should all be banned. Just to name a random few, they include grevilleas,  pine trees, maples, daisy bushes, buttercups, gingko trees, pigface, oleanders, vinca, Hoya, citrus (leaves), tomatoes, heliotropes, box hedges, St John's wort, lupins, ferns of all kinds, and so on, and on, and on... 

Many of them are more dangerous than Cunjevoi. Rhubarb leaves, for example, rate 3 stars for degree of danger. So does Deiffenbachia, a plant which is also advertised for sale in Bunnings. It is an ornamental plant with leaves somewhat resembling Cunjevoi. Green tomatoes and tomato leaves rate 2 stars. Parsley, mint, and quite a few other popular culinary herbs rate 1 star. They are safe in small amounts - and so, probably is cunjevoi - but don't try it!

So why has Cunjevoi, a mere 1-star plant, been singled out for special treatment? It is hard to be certain. I suspect a lack of serious knowledge or research by the petitioner might be the cause.

The petitioner, Gary Duffy, a former One Nation candidate, is clearly a man who takes his responsibilities as a citizen seriously and wants to see wrongs righted wherever he sees them. He has made news previously with other petitions, including a petition to ban off-premise billboards (Dec 2022), and one to have repairs to the Brisbane Valley Highway, in the area where he lives, carried out to a higher standard (Aug 2023). Now he is trying for a ban on Cunjevoi.

I support his view, but only to the extent that I think it is very important that we should all be aware that any plants in our gardens, that are not normally eaten as food, might well be poisonous. This can also apply to parts of plants where other parts of the same plant are well known to be safe to eat.

But as for banning Cunjevoi?

Not really. 

Bottlejong

 Brachychiton x turgidulus

  This year is being a great year for Brachychitons. Toowoomba is aflame with Flame Trees (B. acerifolius). The large, felty pink flowers of Lacebarks (B. discolor) are looking wonderful where they have been planted along the new England Highway at Highfields, and where they still occasionally occur in the remnants of their natural rainforest habitat at Highfields and Gowrie Junction. Locally native Kurrajongs (B. populneus) are heavily in flower along the roadsides, particularly between Goombungee and Meringandan, where their nodding bells are inconspicuous until you slow down for a closer look. And our other local native brachychitons, the Bottle Trees are displaying their creamy-white flowers. The main street in Goombungee is a good place to look for them. There are also many beautiful Brachychiton hybrids, produced and marketed by those clever people in the horticulture industry, to be seen in gardens of the district.

Less familiar is the naturally occurring hybrid between kurrajongs and bottle trees. It occurs often enough to have been given its own name, Brachychiton x turgidulus, and it occurs in places where its parent trees can be found somewhere nearby. We call it a bottlejong.

Bottlejong

Its flowers take some of the characteristics of their parents. Their redness comes from the kurrajong, but they are usually redder. Compare this photo  with the kurrajongs below.

 

Kurrajong. Minimally red. Note the shorter lobes.

 

Kurrajong, tree 2. Greener flowers, with a red centre.

Kurrajong, tree 3. Strongly red flowers

 

The white backs of the Bottlejong,together with their subtle hairiness, come from the bottle tree parent. The flowers of bottle trees also vary naturally a little both in their hairiness and their colour. They can be white or cream, and may have some red speckling..

Bottle tree. A very white flower.

A different bottle tree. A hairier flower, with a few red speckles.

 In shape Bottlejongs are part-way between parents, with lobes longer than the kurrajong, but shorter than the bottle tree, in relation to the overall length of the flower. Note also the different colour of the flower back of the hybrid, in relation to its kurrajong parent. 

Kurrajong. Rounded bell, green on back.

Bottlejong, wider flowers, with whitish, V-shaped back.

The trunk of the Bottlejong is stouter at the base than the trunk of a true kurrajong (for which it is often mistaken) but not as stout as a bottle tree trunk. "Turgid" means swollen, and it is the wide trunk that distinguishes the hybrid from  kurrajong, and has given Brachychiton x turgidulus its name.

Wide flowered Kurrajong, Brachychiton x turgidulus

 

Kurrajong, Brachychiton populneus. Note the straight trunk.

Bottle tree, Brachychiton rupestris.

Because they are so often mistaken for kurrajongs until they reach the age of flowering, which may take 20 or 30 years, young hybrids go unnoticed. We are uncertain whether their leaf-shape has the same variability as their parents.  Like its parents, it usually drops most of its leaves before flowering. In its best flowering years, such as this one, the leaf-drop may be complete, with new leaves coming in as the flowers begin to die.

I only know, personally, of a few of these trees. I have been told that they are quite widespread around Toowoomba and the Darling Downs, however, so would be interested to hear from any readers who  are aware of this interesting plant.

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