Rare 'hair ice' discovered in Bracklinn Woods
National park rangers have found a rare form of ice covering dozens of pieces of dead wood in woodland near Callander.
The "hair ice" is a highly unusual type of frost that needs a very particular set of conditions to form.
Suzanne Humphris, a ranger team leader for the Loch Lomond and the Trossachs National Park, discovered the ice in the Bracklinn Woods on Friday.
The strange, candy floss look is caused by a fungus called exidiopsis effusa.
The action of the fungus is to enable the ice to form very thin hairs - with a diameter of about 0.01mm - and to keep this shape for many hours when temperatures are close to freezing.
Ms Humphris told BBC Scotland: "It looks like snow or fungus growing from wood, but it melts in your hand when you touch it - it instantly disappears.
"I've never seen so much of it. If there's other frost around you don't really notice it, but there wasn't this time so it stood out."
The ice only appears on wood which has fungus growing in it and there also needs to be exactly the right combination of humidity and temperature.
Ms Humphris said: "The conditions are to have lots of water in the wood, humid air and for it to be below freezing."
A study by scientists at the University of Bern in Switzerland, published in July 2015, linked the formation of hair ice to the exidiopsis effusa fungus.