New data on the distribution, biology, intra- and inter-population variability and conservation state of Sicilian populations ofAnacolia webbiiare provided. Two new localities are reported, so that total five fragmented populations occur in the island, all of them in a rather small area in the western part of the province of Palermo. They live on wet limestone or sandstone cliffs with base at 900–1200 m a.s.l. and N, N-NE aspect, within communities ofAceri campestris-Querco-ilicis sigmetum. The plants are particularly vigorous, but some data suggest a condition of vulnerability of the populations. In fact, in addition to specificity to a rare habitat on the island, a morphometric and allozyme analysis showed a very low genetic and morphological diversity. One population (Costa Lunga), showing small morphological differences with respect to the other populations, diverges from this pattern, showing the highest mean number of alleles per locus (1.5), the highest polymorphism (50%) and intra-population diversity (H = 0.249). In one of the larger populations (Mount Kumeta), moreover, a remarkable presence of sterile plants, a paucity of male plants as well as a low production of sporophytes and a high rate of aborted archegonia have been recorded. [ABSTRACT FROM PUBLISHER]