The disruption of the Covid pandemic seems to go on forever; hospital admissions for Covid are rising and everyone is urged to test before they go anywhere which leads to lots of isolated young people and unvisited grannies. It’s hard to feel positive as the new year begins even though the Omicron variant may be milder and many people hardly notice any symptoms.
In this post I’m getting away from all that to look at lichens. These organisms which most people hardly notice are very sensitive yet incredibly tough and also beautiful, with a life strategy based on the strength of co-operation.
Lichens are all around us, growing on roadside trees we pass every day but people are often too busy going somewhere or too absorbed in themselves to see them.
Lichens also grow on old gravestones, adding living embellishments to the commemoration of the dead.
In the 1700s the botanist Carl Linnaeus studied lichens, then thought to be plants, and gave some of them scientific Latin names as he attempted to slot all living things into kingdoms, classes, orders and species. Since then it’s been discovered that lichens are not plants but are a combination of a fungus and a green algae or cyanobacteria. These organisms live in one body in a mutually supportive relationship known as symbiosis. The fungus provides structure and the algae and cyanobacteria provide food through photosynthesis. It’s a very successful partnership and lichenologists have now identified and named around 18,000 lichens living everywhere from the Arctic to the Antarctic. Many of them are very beautiful when magnified.
Lichens are also indicators if air pollution; although some species will tolerate pollution others will only grow where the air is pure. The Natural History Museum website explains this very well at HTTPS://WWW.NHM.AC.UK/DISCOVER/NATURE-AND-POLLUTION-WHAT-LICHENS-TELL-US-ABOUT-TOXIC-AIR.HTML
Lichens may be sensitive but they’re also tremendously tough: they can survive in a greater range of latitudes and altitudes than most other organisms and can even survive a visit to outer space; here’s an extract from The New Scientist Magazine, 21 Jan 2021
‘Lichens have the ability to shut down, allowing them to tolerate extreme desiccation in a dormant state. They recover quickly when conditions improve, restarting photosynthesis and growth. Two lichens took a trip on a Russian Soyuz rocket in 2005. They were exposed to the vacuum environment and cosmic radiation of open space for 15 days. On their return to Earth, their ability to photosynthesise was unaffected. It would be a fair bet for lichens to be one of the last living life forms on a dying Earth.’
Read more at: https://www.newscientist.com/lastword/mg24933191-100-how-do-lichens-survive-on-baking-hot-roofs/#ixzz7FswOPYO0
Lichens are often un-noticed but through them I glimpse the magnificent nature of the world beyond myself and my fidgety human anxieties. I also love their wonderful Latin names and I’ve written them an ode, a poetic form which is, according to Wikipedia ‘an elaborately structured poem praising or glorifying an event or individual, describing nature intellectually as well as emotionally.’
ODE TO LICHENS For Linnaeus all life was notable, he allocated double barrelled names to scabs and shreds on trees and stones, now hundreds of lichens too insignificant to merit an English title are awarded a resonant Latin appellation. In acid towns ragged yellow circles on roofs where seagulls squawk and shit are dubbed Xanthora paretina, On gravestones in country churchyards Leconora muralis jostles for space in a chaos of crusty decorations. In quiet woods Graphis scripta scribbles small hieroglyphics on hazel trees, on rotting stumps Cladonia coccifera raises bright omens of a rosy future, in the purest air Lobaria pulmonaria inhales the sun through mock alveoli. Under Arctic snow lies reindeer manna Cladonia rangiferina, Usnea longissima garlands temperate forests, Dimelaena radiata clings to desert stones and in the wastes of Antarctica Xanthoria elegans and Buellia frigida splodge orange and black on the icy rocks. In lichen’s beginning, in a turmoil of competing lives beyond imagination, fungi, algae and cyanobacteria wrapped their bodies in each other and, forsaking their separate selves, secured the blessings of symbiosis. Now lichens creep over the land in a smudge of insignificance, but maybe before the sun begins to die and when the planet no longer sustains a species that assumes its individuals are the pinnacle of creation, the incredibly meek lichens shall inherit the earth. Anne Bryan