It always interests to me how much wildlife there is in European inner city areas. I don’t mean the odd robin or ladybird but things you really might not expect to be tucked in between tall buildings, heavy traffic and paved streets. Areas where nature has reclaimed land back from humans have enchanted me as long as I can remember. Growing up on an almost deserted island in the middle of Hong Kong where bamboo and banana had removed most traces of human impact, had left a lasting impression on my young mind. I would look out in the evenings from the beach which was our front garden, across the water, to see the lights of skyscrapers and the densely populated metropolis. But behind me lurked the dense semi-tropical forest of our back garden; a forest rich with wildlife, with cockatoos, snakes, soldier ants and who only knows what else. But you don’t have to travel to the Far East to find the same kind of fusion of nature and city, even capital city.

Take Berlin, for example. Almost bang splat in the middle of the German capital a park popped up, remodelling recovered land from an old overgrown pre-war railway siding. A lot of imagination went into the design and lawns were seeded, trees and undergrowth were cleared, paths being laid. But parts of the the old siding where there was a high concentration of old and partially buried railroad tracks were left as they were, microcosms of pure nature. Living even in these quite small patches of unkempt woodland are some of the most remarkable things which almost all visitors to the park walk right past without noticing. Many times I have been out with the dog, walking along the path, when a buzzard with a wingspan of almost one and a half meters swoops down from a tree right above the heads of unsuspecting people who carry on walking unaware of how close they came to such an amazing raptor. More often, the buzzards are flying high above the meadows in an age old aerial dog fight with the resident crows; the crows mobbing it in the vain hope of chasing it off their patch. This is a battle which has gone on for tens of thousands of years.

Glancing between the low-level buzzard swoops and the ariel dog fights, hiding in plain view, are numerous large tangled spheres of magic which nestle upon the upper branches of the trees. Mistletoe (Viscum album), a parasite, lives in the boughs of trees and extracts fluid and nutrients from its host and only relies upon photosynthesis when young and while establishing itself properly on the host. The dark irony of Mistletoe is that it kills its tree hosts but also provides food and shelter for lots of animal species, particularly the mistle thrush (Turdus viscivorus), and considerably increases pollen transfer and biodiversity. There is silver lining to its dark cloud.

Although mistletoe grows on many trees it was particularly revered by the ancient Celtic druids when found on the branches of oak trees. Druids had a very special relationship with oak trees and some think they got their name from two elements of Proto-Celtic: derwo-weyd - (oak-see) or druwid (strong-see); meaning, perhaps, ‘oak knowledge’ or ‘strong knowledge’. Pliny the Elder alluded to ‘druid’ meaning ‘oak knower’. The statue of the Celtic Prince of Glauberg, excavated at Glauberg in Germany in 1996 with his mistletoe shaped headdress, confirms this relationship with mistletoe. Pliny describes a remarkable ceremony involving oaks, mistletoe, golden sickles, white oxen and druids in white robes climbing trees. Apart from the oxen his story could be straight out of a volume of Asterix the Gaul. For the Greeks, druids and mistletoe were inseparable.

Mistletoe played a hugely important role in Europe of the bronze age and early iron age. It was probably used as a cure all, a homeopathic remedy (a poison to cure a poisoning) and, ground to a porridge, as a wound dressing. Due to its light and milky translucent berry and the viscous, tacky, milky juice of the berry (hence the name Viscum album), it was also believed to aid fertility and some people today in England still hang branches from door frames (even though most modern door frames are no longer oak), hoping for a hapless maiden to tarry beneath and be obliged to surrender a kiss.

I always feel a tad sad for the mistletoe growing as big green orbs in trees, almost forgotten despite the thousands of years we have had a relationship with it and despite the importance it has played in our culture. I’ve always had a strong affection for the oak tree and the mistletoe. I used to wonder if the oak and mistletoe have attributes which innately draw some people to them. That mistletoe is a plant which lives its entire life without needing soil is something which continues to delight me. I’m always thrilled when walking the dog and I happen upon some fallen mistletoe twigs. I excitedly tuck them into my pocket and, almost coddling them, bring them home to live with me for a while. Druids might have frowned upon collecting mistletoe which had fallen to ground and been tainted by the Earth, but I am not about to put on a white robe and—golden sickle in hand—climb an oak tree in the middle of the park to collect it their way.

Next time you are in the woods, or even a city park, and notice the amazing blobs of yellowish green tangled twigs and leaves take a moment to reflect. Remember the ecological contribution this quiet killer makes to biodiversity. And when you next witness a young boy chasing the apple of his eye through your home with a sprig of mistletoe held high above his head—the object of his affection running as fast as possible to escape him, chortling frantically—give a brief thought to the immense importance this simple and almost neglected plant has had in the cultural and religious history of our species and the early formation of our pharmaceutical enlightenment. Consider for just a moment how such ancient customs have survived thousands of years and live on in the midst of our world of computers and space travel, even if the true underlying meaning and significance of the customs have long been forgotten and how, through the murky shadows of time we can still spy in ourselves traces of our ancient Celtic forefathers.