Rhizocarpon geographicum is known in English as the Map Lichen, for its cadastral map look. It is a striking lichen that grows very slowly indeed always on hard surfaces such as rocks or rocky walls. We do have a very small piece growing on the brick paving in the front of our house, but it is more usually found in the north and west of the United Kingdom.
A few of the very slow growing lichens have been used to measure and date the uncovering of the surfaces upon which they grow, for example in modern glacial landscapes and on archaeological sites. This is one of the most popular, if it is found in sufficient quantity on the site being studied.
For now this card comes cellophane wrapped, but this will alter as stocks change. They are blank to allow you to say whatever you would like to say. The accompanying envelope is white