Lichens of the genus Cladina (the reindeer lichens) are commonly used as ornaments, including for dioramas with model trains, where they make bushes and tree crowns. Our fungi and lichens Collections Manager Robert Lücking used to have a model train when he was young and remembers spending many hours building the diorama, setting up small areas of forest and bush using differently colored lichens. He had no idea at that point that he would actually study lichens scientifically when grown up. Nowadays he prefers to observe them in the field, but each time he comes across a reindeer lichen, he is reminded of his model train diorama. And he remains a great fan of model trains.
Model train diorama photographed in Germany