Contribution to the lichen flora of the Northern Black Forest. Records of lichen species from the National Park Black Forest are listed and some typical associations mentioned. Particularly characteristic are communities which prefer old stems of Abies and Picea, on rather rain-protected faces with Lecanactis abietina, on wet faces with Thelotrema lepadinum and rarely with Sphaerophorus globosus, towards their basis with Micarea species as M. adnata and M. cinerea. On dead stems communities with Calicium glaucellum, Chaenotheca and Chaenothecopsis species are widespread. On sandstone boulders Lecidea lithophila and L. plana are most frequent; on steep faces protected from rapid drying the Fuscideetum kochianae is typical. On raw humus covers of Trapeliopsis granulosa, Placynthiella uliginosa and P. oligotropha form mosaics with communities rich in Cladonia species. The area is dominated by conifer woods and excludes human settlements, therefore man-made substrates and subneutral bark habitats are of minor importance concerning their frequency; nevertheless, they increase the species diversity considerably. Ramboldia cinnabarina is new to Germany. Key words: lichens, Northern Black Forest, National Park, forests, boulder slopes.