Exsiccata is a work with "published, uniform, numbered set of preserved specimens distributed with printed labels". Typically, exsiccatae refer to numbered collections of dried herbarium specimens respectively preserved biological samples published in several duplicate sets with a common theme/ title like Lichenes Helvetici . Exsiccatae are regarded as scientific contributions of the editor with characteristics from the library world and features from the herbarium world . Exsiccatae works represent a special method of scholarly communication. The text in the printed matters/published booklets is basically a list of labels with informations on each single numbered exsiccatal unit. Extensions of the concept occur.