<br> The taxonomy of<br> Protoblastenia<br> in Finland was studied, based on morphology and molecular data (nuITS rDNA sequences). Twenty species were recognised, with sixteen species being newly described here:<br> P. arupii<br> sp. nov.<br> ,<br> P. borealis<br> sp. nov.<br> ,<br> P. compressa<br> sp. nov.<br> ,<br> P. dolomitica<br> sp. nov.<br> ,<br> P. ekmanii<br> sp. nov.<br> ,<br> P. fennoarctica<br> sp. nov.<br> ,<br> P. minuta<br> sp. nov.<br> ,<br> P. oulankaensis<br> sp. nov.<br> ,<br> P. pseudocompressa<br> sp. nov.<br> ,<br> P. pseudoterricola<br> sp. nov.<br> ,<br> P. remota<br> sp. nov.<br> ,<br> P. rikkinenii<br> sp. nov.<br> ,<br> P. saanaensis<br> sp. nov.<br> ,<br> P. timdalii<br> sp. nov.<br> ,<br> P. violacea<br> sp. nov.<br> and<br> P. westbergii<br> sp. nov.<br> All species are confined to calcareous rocks, except<br> P. terricola<br> which also grows on calcareous soil. The calcareous fells in Enontekiö in NW Finland were identified as hot spots of<br> Protoblastenia<br> diversity. Nine newly-described species (<br> P. arupii<br> ,<br> P. fennoarctica<br> ,<br> P. minuta<br> ,<br> P. pseudoterricola<br> ,<br> P. rikkinenii<br> ,<br> P. saanaensis<br> ,<br> P. timdalii<br> ,<br> P. violacea<br> and<br> P. westbergii<br> ) are restricted to this area in Finland. Several of the species are semi-cryptic. On average, they may have minor morphological differences, but many specimens cannot be identified, based on morphology only.<br> Protoblastenia rikkinenii<br> is reported from Norway and<br> P. oulankaensis<br> from Italy, based on GenBank sequences. Full descriptions and a preliminary key of<br> Protoblastenia<br> in Finland are provided.<br>