It seems apt that mushrooms are made from the same stuff as insects – chitin – because, like insects, they have a gift for sudden appearance. One moment nothing, then, as if on wings, they descend everywhere. We must acknowledge that this fungal sense of the dramatic relies partly on us. We simply fail to notice something so lowly, so brown, so inhuman, and yet so fundamental to life, until it does something eye-catching.
In our garden the best display has been mounted on the back lawn. Despite a fey hint of Gallic artistry or culinary sophistication in the name – and they are said to be delicious – some of these fairy ring champignon look like small crumpled turds.
The one undeniable flourish in their appearance is the circle they have inscribed on the grass. What I find just as compelling is the way the lawn is so much greener precisely where they’ve reared their mouldy heads.
I can infer the organism’s subterranean habits from the appearance of those fruiting bodies – the mushrooms themselves – and from the fresher colour in the lawn. In that lightless place the main organism, known as the mycelium, is entwined with filaments that are finer than spun silk.
A single fibre, known as a hypha, is 100th of a millimetre thick. Yet in a single kilo of woodland soil there can be 200km of hyphae, and underneath an entire wood there will be millions of kilometres of these living pathways. There they traffic in nutrients, processing the hard lignin and resistant woody tissues – five tonnes of this vegetable junk per hectare is dumped annually – and converting it into elements that trees and flowers can re-use. That orbit of green in the middle of our lawn is a result of the nitrogen processed by fairy ring champignon.
That circle of colour speaks truly of the underworld. Some fungi are treacherous, some are highly destructive, some even deadly poisonous, and we often clothe their names in images of Hadean darkness. Yet they are the black stuff that, come spring, helps bring Persephone’s radiance to all our lives.
• Forty Years on the Welsh Bird Islands, the 2015 memorial lecture in honour of the late Country diarist William Condry, will be given in Machynlleth on 3 October by Professor Tim Birkhead.