Abstract
49 taxa among the 71 present in Algeria have been inventoried. The IUCN Red List assessment revealed Silene sessionis to be "Endangered", S. aristidis "Vulnerable" and S. auriculifolia "Critically Endangered". Threats to their natural habitat are quarries, sport climbing and shotcrete. Nine of the ten karyologically studied taxa are with 2n = 2x = 24, including the endemics S. sessionis, S. atlantica and S. reticulata; only S vulgaris subsp. vulgaris is with 2n = 4x = 48. The phylogenetic approach confirms the polyphyly of North African taxa which are distributed over eight different sections. Seven taxa show taxonomic ambiguities, three of which are due to nomenclatural confusion in the type specimens of Linnaeus in the group S. mutabilis-S nocturna-S. neglecta. The S. rubella group was found to consist of two different species S. turbinata and S. diversifolia. S. villosa and S. reverchonii occupy questionable positions on the tree, impossible to explain due to the lack of complete herbarium samples. The probable presence of a new species to Morocco has been detected (to be confirmed by morphological characterization).