The Lichen Herbarium contains (as per 2014) 90 000 lichens. The majority is from Norway, but there are also larger, important collections of lichens from North America (T. Tønsberg), Bouvet Island and Antarctica (T. Engelskjøn).
Important collectors are J.J. Havaas, J.M. Norman (part of his collection) and T. Tønsberg. The entire lichen collection has been data recorded and the c. 50 000 lichens collected in Norway can be searched for in the common”Norsk Lav Database” (NLD). From this link/connection there is information on red-listed lichens in Norway. T. Tønsberg at the lichen herbarium publishes the lichen exsiccate “Lichenes isidiosi et sorediosi crustacei exsiccati”.