The lichen collections at University of Helsinki (H) include approximately 460 000 specimens, of which ca. 50 000 have been databased so far. H houses specimens from all continents, but most well-represented regions include the Nordic countries, boreal Russia, Canada, Tierra del Fuego, and Patagonia. Particularly abundant are the genera Cladonia and Peltigera. The invaluable historical collections of E. Acharius (H-ACH, 5 500 specimens) and W. Nylander (H-NYL, 52 000 specimens) are kept separately, as is the collection of type specimens (11 000 types databased so far). 160 series of lichen exsiccatae are in part kept separately but mostly incorporated in the collections. Notable collectors include T. Ahti, M. Brenner, L. Fagerström, E. Häyrén, A. Henssen, A. Koskinen, V. Kujala, G. Lång, M. Laurila, J. P. Norrlin, V. Räsänen, H. Roivainen, E. A. Vainio, and O. Vitikainen.