As summer moves towards autumn, and grassland flowers fade, a second show of colour can be provided by fungi. Among the most colourful are the waxcaps. In permanent pasture that has not been “improved” by the addition of fertilizer or lime these little mushrooms can put on an impressive display. Grassland waxcaps are one example of a diverse and important group of organisms – the fungi.
The fungi comprise a Kingdom of life. This means they are one of a handful of fundamental groups into which all life can be classified. Fungi are distinct from both plants and animals, although on the tree of life they are actually closer to animals. Life originated some 3.5 billion years ago and the Kingdoms we know today began as early solutions to the problem of staying alive. The successful pioneers set off on separate evolutionary pathways that have, through millions of years of evolution, produced the species we see today.
Science has not reached a consensus on how many Kingdoms of life there are, but we are all familiar with two – animals and plants. In the natural environment life is most obviously either plant or animal. So, how is it that a whole Kingdom, comprising an estimated 1.5 million species, remains so invisible? Well, granted, a fungus fruiting body (the spore bearing structure) is often visible and can be brightly coloured and come in a variety of bizarre shapes as well as the familiar stalked caps and brackets. But these reproductive structures are mostly short-lived and the fungus spends most of its life hidden away as a microscopic network of fine threads. These threads, called hyphae, grow in search of food which they consume by exuding digestive enzymes and then absorbing the resulting chemical soup.
It is not surprising that many of us are wary of fungi: poisonous species can look alarmingly like edible ones, fungi rot our homes and possessions and they cause disease in us and in our domesticated crops and livestock. Yet the fact is the positive role of fungi cannot be overstated. Around 90% of the world’s plants have fungi forming intimate associations with their roots, thereby gaining access to nutrients and water beyond their lonely reach. In return the fungi receive some of the surplus sugars manufactured by the plant. Crucially, fungi recycle the dead remains of living things, making the chemical compounds in them available again as the building blocks for new life.
So next time you are in a flower-rich grassland spare a moment to consider the unseen fungi that are keeping things ticking over nicely below ground. And when you see some magnificent, weird or wonderful fungus ponder on how important these organisms are in our environment. Their Kingdom is a vast terra incognita, where perhaps more than 90% of the world’s fungi are yet to be named and described by science.
Waxcap fungi © Laurie Campbell