We conducted a phytosociological study of the communities hosting the rare and endangered fern Adiantum capillus-veneris in the foothills of the Julian Alps, in Karst and in Istria. Based on a comparison with similar communities elsewhere in the southern Alps (northern Italy) we classified most of the recorded stands into the syntaxa Eucladio-Adiantetum eucladietosum and -cratoneuretosum commutati. Releves from the southern Julian Alps, located in comparatively slightly colder and moister local climate and the dolomite bedrock are classified into the new subassociation -hymenostylietosum recurvirostri subass. nova. Stands with the abundant occurrence of the liverwort Conocephalum conicum, are classified in to the new subassociation -conocephaletosum conici subass. nova. Stands in conglomerate rock shelters along the Soča at Solkan are classified into the new association Phyteumato columnae-Adiantetum ass. nova, a community of transitional character between the classes Adiantetea capilli-veneris and Asplenietea trichomanis. Fitocenološko smo raziskali združbe, v katerih v prigorju Julijskih Alp, na Krasu in v Istri uspeva redka in ogrožena praprot Adiantum capillus-veneris. Na podlagi primerjav s podobnimi združbami drugod v južnih Alpah (severna Italija) smo večino popisanih sestojev uvrstili v sintaksona Eucladio-Adiantetum eucladietosum in -cratoneuretosum commutati. Popise iz južnih Julijskih Alp, ki smo jih naredili v nekoliko hladnejšem in bolj vlažnem krajevnem podnebju in na dolomitni podlagi uvrščamo v novo subasociacijo -hymenostylietosum recurvirostri subass. nova. Sestoje, kjer je obilno uspeval jetrenjak Conocephalum conicum, smo uvrstili v novo subasociacijo -conocephaletosum conici subass. nova. Sestoje v konglomeratnih spodmolih ob Soči pri Solkanu uvrščamo v novo asociacijo Phyteumato columnae-Adiantetum ass. nova, saj kažejo na stik združb dveh razredov Adiantetea capilli-veneris in Asplenietea trichomanis.