Wednesday, 25 January 2012

Blue quandong: tree of many colours


Not that you would know from the way I've been avoiding the subject, but the blue quandongs (Elaeocarpus angustifolia, syn. E. grandis) are flowering at the moment.

1 January 2012


24 January 2012


25 January 2012


They are magnificent trees, although not really suitable for small gardens. Not only do they grow rapidly, but they also spread out. Mature trees are buttressed (I'm sure we can all identify with that) and have extensive crowns. They also do this.

Still, if you've got the space, they are stunning to look at. Leaves are light green, turning scarlet before they fall. As with most vine forest trees, leaves drop throughout the year, so there is always a decorative highlight or two.

1 January 2012


The fruit has pale green flesh enclosed in an iridescent blue skin. Botanist David Lee uncovered the source of the blue colour — it is not a pigment, as is the case with many other fruit, but a property of the microscopic structure of the skin. It is produced by multi-layer interference in a similar way to the iridescent blue of bird feathers and butterfly wings. [Some of the links are dead in that post. I will have to write an updated version.]

In Nature's Palette, Lee writes:
This tree is sacred in India, where the stony inner fruit is highly ornamented and used for bracelets and necklaces (malas) for reciting prayers and sacred sounds. The sadhus (spiritual seekers) wandering the countryside frequently carry malas of rudraksha [local name for the tree] beads...I discovered that the interference color of the rudraksha fruits is indeed produced by a structure whose cellulose layers are of the predicted thickness to produce blue. This structure, which I have called an "iridosome", is different from those seen in leaves; it is secreted by the epidermal cells of the fruit and is located outside the cell membrane but inside the cell wall.

20 November 2011


Despite their attractive appearance, the fruit are not much favoured by the pademelons. They take a bite and then move on, so forest floor is littered with barely nibbled ripe quandongs. Wompoo and topknot pigeons, spotted catbirds and tooth-billed bowerbirds, on the other hand, make the most of the all you can eat buffet.

20 November 2011

The seeds are enclosed in a wrinkled endocarp that looks a bit like a brain after a night without sleep because of an owl. They are also plentiful on the forest floor. (Better pictures here.) It's a wonder that everything isn't coming up quandongs.

25 January 2012

Reference
Lee, D. (2007). Nature's Palette: The Science of Plant Color. University of Chicago Press.

6 comments:

John Bates said...

very pleased to have found your blog. my name is john & i have lived west of gordonvale for many years, in a patch of remnant vine forest. the reason why i'm commenting is i was recently given some ripe blue quandong fruit; & i was wondering if you knew anything about growing the trees...plenty of room here for a big rainforest tree which would add to the diversity of native foods.thanks in advance.

Snail said...

(Oh, that's annoying! I wrote a long comment and the internet ate it.)

Someone asked me the same thing a few days ago, so I've been digging around on the internet for info. As far as I can tell, they are very slow to germinate (up to two years), so --- if you're as impatient as me --- that's a bit of a pain. I understand that filing the seed or fermenting it a bit might speed up the process. The catbirds, bowerbirds, wompoo and topknot pigeons and cassowaries all eat the fruit, so I guess they benefit from the journey through a bird's gut or a treatment that exposes them to similar conditions.

I'll ask the folk at TREAT (Trees for the Evelyn and Atherton Tablelands), because they have lots of experience with this sort of thing. If they can shed any light on the best way to grow quandongs, I'll write a post on it. Could take a few days, though.

They are spectacular trees, but are very quick to shed limbs, so probably not one to put too close to the house.


John Bates said...

thanks for fast response. i'm new to this internet thing myself so i'm not suprised when things get "eaten"!

Dinesh Babu Rengasamy said...

ha.. just now seeing this link..I am Dinesh and i am doing a research on various species of rudraksha
which is called blue quandong in Australia.I am from india and in india
it is difficult to find Elaeocarpus angustifolia and we can only find
elaeocarpus ganitrus.I need to examine the fruits of Elaeocarpus
angustifolia and if possible i would like to grow that species here in
my garden. So can you please send me some of the fully ripened fruits
of various sizes.I would be very thankful.Please reply as soon as
possible.

Garry Dodds said...

Blue Quandong trees grow in the damper forests along the Eastern Sea Board of Australia. The blue nuts can be found laying on bush roads/tracks in summer. Doesn't matter if you run over them- actually grinding some of the nut hull away encourages germination especially if you soak them in hot water after grinding. Regards Garry Dodds

MJ said...

Garry is correct. I own a plant nursery and scarification of the seed with sandpaper then soaking in hot water will help speed germination.