Reindeer moss
By Daniel Butler, author and forager
We may be approaching the height of the main mushroom season, but the woods contain plenty of other points of fungal interest. Reindeer moss (Cladonia stellaris) is generally overlooked, yet arguably one of the world’s most important fungi.
Now one glance at reindeer moss shows it is not a ‘true’ mushroom is the normal sense of the word. Instead as a lichen it falls within the fungal kingdom, but as an organism which lives in the taxonomic twighlight zone: half-plant, half-mushroom.
Reindeer lichen is more accurate than reindeer moss (Photo: Author's own)
But to return to the main point. It cloaks the permafrost with 15 cm-deep carpet. In Canada alone it covers four million square kilometres: add in Scandinavia, Russia and Alaska and it cloaks well over 10 million square kilometres. Not only is it a vital component in sustaining the hardy animals upon which so many nomadic Arctic peoples depend, but it represents a vast carbon sink, absorbing billions of tonnes of carbon dioxide each year and locking it up for millennia in the form of peat buried beneath the snow.
Plants really struggle to survive in such areas because they have high water requirements. Regardless of the almost ever-present snow, these wastes are effectively deserts with all liquid water locked away for at least seven or eight months of the year. Worse, although most add natural anti-freeze to the inevitable liquid inside their cells, in ultra-cold periods this still freezes and expands to burst the walls. Indeed, trees can actually explode in exceptionally low temperatures. Life is much more difficult for smaller plants unless they grow close to the ground and lie dormant through the long winter under a thick layer of insulating snow.
Soviet soldiers were sent into battle with Usnea lichens as a field dressing
(Photo: Archive)
Lichens, however, are ‘ultra-survivors’. Despite being incredibly slow-growing (reindeer lichen grows at 3 – 5mm a year) they have developed strategies to thrive in places where plants cannot cope. In this case the lichen produces its own herbicides which soak into the surrounding soil. Once there, these prevent plant competitors by inhibiting seed germination and stifling early growth. The lichen also shrinks on drying. When rewetted it expands to rip nearby plant seedlings clear from the soil. This might explain why – if one uses the word fungi loosely – it is the world’s most common fungus.
It has three main uses for the human forager. As with many Usnea lichens, it has proven anti-bacterial and anti-viral qualities (indeed a near-relative was used as a field dressing by Russian soldiers fighting on the Eastern Front in WWII). It is also laced with vitamins and minerals, but it is indifferent in edibility. Nevertheless, it can make an interesting garnish for a dish or as an unusual texture for Asian-inspired dishes.