Endemic Oncocyclus irises of Lebanon are represented by a complex of 4 taxa close morphologically and replacing each other over short distances in distinct populations. All these taxa are threatened and they represent a interesting model for conservation biology in the eastern Mediterranean.The persistence of half of the historical populations was confirmed through an update of their distribution. Several threats, specially human threats, are responsible of the disappearance of historical occurrences and / or threaten actual populations.A morphological characterization, coupled to the study of the genetic structure, has shown a inter population variation relevant of a taxonomic group in the course of differentiation. All the studied populations showed high levels of genetic diversity. However, a trend towards decreasing diversity with a decreasing size of populations was shown.A study of demographic structure and reproductive success was indicative of a good viability of large populations while several elements, in particular environmental stochasticity, threaten small populations. An original pollination mode, based on a bimodal system, was shown in Lebanese Oncocyclus. Last, proposals for the conservation of these threatened endemic taxa are given in the Lebanese context. Their management will have first to focus on eliminating direct threats to the habitats. Re-enforcement or translocation measures represent solutions for the preservation of these taxa.