The Countryside Council for Wales (CCW) has identified 20 different types of waxcap toadstools which have not only survived on land which the army uses to train Nato troops, but are thriving.
The council has begun the process of having a hectare-size meadow on the range in mid-Wales declared a Site of Special Scientific Interest, the first designed solely for the protection of British fungi.
The CCW has produced a leaflet with photographs of the waxcaps to help identify them.
Churchyards and lawns
Roy Woods, the organisation's fungi and lichen protection officer, said the need to protect the toadstools was sparked after reading about how continental conservationists lamented the decline of their native species.
Britain has, by contract, inadvertently created a number of safe havens for wild fungi forms, he said.
Well-kept churchyards and the lawns of country houses often play host to the toadstools which are encouraged by grass that is mown regularly.
But military ranges provide even greater protection for the fungi whose numbers have been greatly reduced by the loss of their natural habitat.
The army's Epynt ranges offer two conditions in which the toadstools thrive: the grass is closely cropped by sheep which are allowed to roam freely, and the soil has benefited from being free from fertilisers for decades.
Conservation centre
The toadstools hate enriched soils and can only spore well in short-cut grass.
Eypnt offers both these conditions and the meadow directly behind the army's conservation centre on the ranges is the site which the CCW hopes to have declared an SSI.
Mr Woods said up to 20 species of the fungi could inhabit the same piece of ground without apparently trying to out compete each other.
He said: "We just do not know what they feed on or why they do not compete against one another.
"They are all so different; some are white, some are blue, others are red, green, slimy or dry, and all are in our backyard so to speak.
"Our aim is to manage things more positively."