27 December, 2011

Under the mistletoe

With the arrival of Christmas, I figured it was time to come up with a relevant blog post. A quick Google search for Christmas and the Barwon landed me several hundred places to stay in Barwon Heads over the summer holidays, a Christmas cheerio from Barwon Water and details of an 1850s Christmas exhibition at Barwon Grange.
Aside from this, there appears to be little in the way of formal Christmas tradition attached to the Barwon River. I'm sure many local families have their own Christmas traditions associated with the river. Our ride yesterday afternoon revealed waterskiiers making the most of the weather, a variety of kids testing out new bikes and remote-controlled toys - no doubt received for Christmas - whilst for the last couple of years our own post-lunch stroll on Christmas day has been along the banks of the Barwon.
Okay, so I needed to find a different angle. Nothing came to mind, but then, a few days before Christmas, a local paper ran an article about mistletoe - what could be more Christmassy than mistletoe?
European Mistletoe, taken from www.plantlife.ort.uk
In Australia? Well, almost anything really. Mistletoe as Europeans know it or the similar plant found in America is not found in Australia and isn't much a part of our Christmas tradition. We do however have around 90 different species of mistletoe of our own.
So what is mistletoe? It is a partly parasitic plant which grows on the branches of a host tree from which it draws nutrients and water to supplement its own photosynthesis. Mistletoe is pollinated either by birds or insects who then transfer its seeds to other host plants via their faeces or on their beaks. Mistletoe seeds contain a sticky substance which binds them to the branch of the host until the seed germinates and a more permanent connection is made via a root which grows into the bark.
Australian mistletoe varieties belong to the family Loranthaceae and to the genera Amyema and Lysiana whilst Europe has only the one species of mistletoe from the Viscaceae family and the genus Viscum. American mistletoe belongs to the genus Phoradendron which aptly enough translates from the Greek as "thief of the tree". There are only two species of mistletoe native to the United States.
The term mistletoe itself is believed to derive from the Anglo-Saxon words "mistal" meaning dung and "tan" meaning twig thus "dung on a twig", probably reflecting the tendency of mistletoe to seed where birds had perched.
Wattle tree infested with multiple bunches of mistletoe, Barwon River,Highton
So, is there mistletoe along the Barwon? Yes, and it didn't take us long to spot some. From what I can tell, it is Amyema preissii - the wire-leaved mistletoe whose preferred host is the wattle and it was on that plant that I found it. It has thin leaves and long drooping red flowers. Prior to European settlement along the Barwon, the Wathaurong people used the seeds and flowers of this plant as a natural sweetener.
Bunch of mistletoe hanging from a wattle tree, Barwon River, Highton
 Likewise, a variety of animals and insects also use mistletoe as a food source. Not surprisingly, Mistletoebirds are known to pollinate wire-leaved mistletoe as are Spiny-cheeked Honeyeaters, however I have not seen mistletoebirds anywhere along the Barwon and have not seen these honeyeaters  on this section of the river (around Queen's Park). I would guess then, that some other variety of honeyeater is getting the job done instead.
Red Wattlebirds and White-plumed Honeyeaters are both in the vicinity and known to take nectar from mistletoe whilst New Holland Honeyeaters are also around. It is possible too that other nocturnal visitors such as possums may help disperse seeds.
Wire-leaved Mistletoe flowers, Barwon River, Highton
A second visit today in order to get some close up shots of our local mistletoe, revealed a more widespread infestation than I had realised. There are several dead wattle trees showing signs of previous mistletoe growth along the walking track below and the edge of Barwon Boulevard above the river through Highton. Several more living wattles have varying amounts of mistletoe hanging from their branches.
I would be interested to know if the responsible authority has measures in place for controlling the spread of mistletoe. Whilst it can be an important food source for a variety of wildlife, it can also become a damaging weed.
I did however, see one example of a win to the wattle.

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