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Saturday 29 December 2012

Mistletoe


 
Mistletoe is, of course, one of those plants associated with Christmas. I had a couple of encounters with Mistletoe during this festive season, but, alas, I regret to report that none of these encounters involved any of the traditional kissing!
I visited my brother and his family in the Norfolk village of Congham near King’s Lynn. As I’ve reported before, this village is located in glorious ancient countryside with at least two nature reserves, of national importance, nearby and old lanes bordered by rich hedgerows and copses of old oaks. I have to report though that the area is becoming increasingly suburbanised and, I imagine, most of its modern inhabitants are commuters who work in nearby towns (perhaps as far away as Peterborough or Norwich). Although I’m sure that many of Congham’s inhabitants do appreciate the quality of their environment, I wouldn’t be surprised to find that many of them just drive through it and never really see it (when I went for walks I rarely encountered anyone on foot – lots of cars speeding through the village though).

Anyway, I digress! My first encounter with Mistletoe was not on a nature reserve, or in a lane, but on an apple tree in the garden of one of my brother’s neighbours; there were three or four plants in the same tree. But the really major sighting was last Thursday (27.12.2012) from the window of the 12:56 train out of King’s Lynn, on my way back to Manchester. In the suburbs of Lynn, in the middle distance, I spotted an urban park bordered by old Lime trees – probably (hybrid) Common Limes (Tilia x europaea). The boughs of many of these trees were conspicuously adorned with the characteristic frozen starbursts of Mistletoe plants; I don’t think I’ve ever seen so much Mistletoe in such a limited area.
The great expert on the British landscape, Oliver Rackham, tells us that: “Mistletoe is a flowering plant usually seen on exotic trees – cultivated apple, hybrid lime, hybrid poplar – with a preference for old specimens ... It has a natural habitat on ancient native trees, especially hawthorns.” He also tells us that there is evidence to suggest that Mistletoe was never a woodland species but a characteristic plant of more open, ancient savannahs. I vividly recall finding it on a Hawthorn bush on the Barnack Hills and Holes nature reserve in Cambridgeshire. It was only after reading Rackham’s book that I realised that I had been afforded a privileged glimpse of a prehistoric landscape!
There is only one species of Mistletoe in Britain: the plant with the scientific name, Viscum album. Worldwide there are many other species, all belonging to the family, Santalaceae.
Mistletoe, like Yellow Rattle which I referred to in the last post, is a hemi-parasite i.e. it derives some of its nourishment from the host tree but also has chlorophyll in its leaves which allows it, like most plants, to synthesise sugars from carbon dioxide in the atmosphere, the process being powered by sunlight. A severe infestation of Mistletoe can actually kill a tree.
Mistletoe seeds are delivered to the host tree by birds. An interesting website, called ‘The Mistletoe Pages: a website about the original mistletoe of western tradition and folklore’ (link below) has more to say about which species of bird are involved:
“[Mistletoe] relies entirely on winter birds for berry, and therefore seed, distribution – so birds are essential. Secondly the white sticky berries of Viscum album are not attractive to many birds – many ignore them as they are looking for red, orange, black or blue berries (mistletoe is the only native British species with white berries) and even if they try them the birds are put off by the super-glue quality of the berry pulp. So which birds do take mistletoe berries? In Britain the answer is largely Mistle Thrushes, whose common name and latin name, Turdus viscivorus, hint at a mistletoe specialism. Other thrushes – including Redwings, Fieldfares etc will also eat the berries. But despite their name Mistle Thrushes aren’t really mistletoe specialists as they occur commonly across the country in areas with no mistletoe, where they will eat many other berries. Furthermore they’re not really very efficient at spreading mistletoe. They usually swallow the whole berry, seed and all, excreting a mass of semi-digested berry pulp and seeds about 30 minutes later. Some of those seeds, still sticky, may stick to a branch where they can germinate. Most will not – often hanging uselessly below a branch. A few other birds will eat mistletoe too, including Waxwings and a few other relatively uncommon species, but the most efficient mistletoe spreading species is the Blackcap. These smart little birds only swallow the berry skin and pulp, wiping each seed off their beak before swallowing – and so they are much more efficient than Mistle Thrushes. Blackcaps in Britain migrate south for the winter, so they have not, traditionally, been a factor in mistletoe distribution in the UK. But changing migration patterns in the last 20-30 years have led to first 100s and now 1000s, of migrant Blackcaps from Germany visiting Britain each winter.”
This website also tells us that the main stronghold for Mistletoe in Britain is in the South and West Midlands, but that the distribution appears to be changing – possibly as either the result of climate change or the changed migration patterns of Blackcaps.

Mistletoe always seems to have been rare or uncommon in the Manchester region. The shoemaker botanist, Richard Buxton, in his flora of 1849, gives only two locations:

“Parasitical upon apple trees. In the neighbourhood of Pilkington and Prestwich.”

Ten years later his contemporary, Leo Grindon reported in more detail:

 “On apple-trees in garden and orchards at Lymm; Warburton; Atherton near Leigh .. Prestwich (also on hawthorns), Knutsford, Baguley and elsewhere, but very sparingly, and generally out of public view or Christmas thieves would have destroyed what little there is.”

Until recently I thought that Mistletoe must be extinct in this region but, amazingly, I now have two sites for it – both in Common Limes in the Didsbury area (I don’t want to be too specific for fear of [modern] “Christmas thieves”!). The photograph above was taken at one of my sites. As Common Limes are - well - common in parks and cemeteries, I can think of plenty of places where it might be worth searching for more local Mistletoe.

Dave Bishop, December 2012.

References:

Rackham, O.  ‘Woodlands’, Collins, 2006.


The Mistletoe Pages: http://mistletoe.org.uk/homewp/

Buxton, R. ‘A Botanical Guide to the Flowering Plants, Ferns, Mosses and Algae Found Indigenous Within Sixteen Miles of Manchester’, Longman And Co., 1849.
 
 
Grindon, L. ‘The Manchester Flora’, William White, 1859.