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Posidonia oceanica meadows are acknowledged as one of the most valuable ecosystems of the Mediterranean Sea. P. oceanica has been historically described as a species typically growing on mobile substrates whose development requires precursor communities. Here we document for the first time the extensive presence of sticky hairs covering P. oceanica seedling roots. Adhesive root hairs allow the seedlings to firmly anchor to rocky substrates with anchorage strength values up to 5.23 N, regardless of the presence of algal cover and to colonise bare rock without the need for precursor assemblages to facilitate settlement. Adhesive root hairs are a morphological trait common on plants living on rocks in high-energy habitats, such as the riverweed Podostemaceae and the seagrass Phyllospadix scouleri. The presence of adhesive root hairs in P. oceanica juveniles suggests a preference of this species for hard substrates. Such an adaptation leads to hypothesize a new microsite driven bottleneck in P. oceanica seedling survival linked to substrate features. The mechanism described can favour plant establishment on rocky substrates, in contrast with traditional paradigms. This feature may have strongly influenced P. oceanica pattern of colonisation through sexual propagules in both the past and present.

A revision of the Capparis spinosa group has been carried out in southern Europe, northern Africa, western and central Asia, in order to provide a uniform taxonomic treatment of its representatives. The xerotropical origin of this group, showing disjunct distribution in several holoarctic and paleotropical regions, is underlined and the different species concepts historically adopted are discussed. In the present treatment a single species is recognized, C. spinosa, represented in the study area by two subspecies. C. spinosa subsp. spinosa shows derived characters, high polymorphism and a wide distribution range from the Mediterranean eastwards to China and Nepal. C. spinosa subsp. rupestris, less variable and showing phenotypic characters closer to the tropical stock of the group, is recorded in the Mediterranean Region and the Sahara. On the basis of herbarium and field investigations, the variability and distribution of the two subspecies are examined. Within each subspecies some varieties are recognized, for which morphological, chorological and autecological data are presented. Four new combinations (C. spinosa subsp. spinosa var. herbacea, C. spinosa subsp. spinosa var. atlantica, C. spinosa subsp. rupestris var. ovata, C. spinosa subsp. rupestris var. myrtifolia) are proposed.

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The variability, autecology and distribution of the Capparis spinosa group have been studied in eastern Africa, Madagascar, southern Asia, Australia and Oceania. In these areas the taxonomic treatment of the group, also represented in holoarctic Regions of the Old World, is still critical. The forms widespread in the study area are here referred to four subspecies of C. spinosa. The recognized subspecies mostly show geographical vicariance, except in some contact areas of the Middle East and western Himalaya. Two nomenclatural novelties, i. e. C. spinosa subsp. cordifolia comb. et stat. nov. and C. spinosa subsp. himalayensis stat. nov., are proposed. Among the recognized taxa, C. spinosa subsp. cartilaginea shows a wide distribution range including eastern Africa, Madagascar, south-western Asia to Pakistan and India, C. spinosa subsp. cordifolia is widespread in the Pacific from Indonesia eastwards to Pitcairn Islands and Hawaii, C. spinosa subsp. nummularia is recorded from western, central and northern Australia, C. spinosa subsp. himalayensis is known from Pakistan, India and Nepal.

23 24In order to empirically assess the effect of actual seed sampling strategy on genetic 25 diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the 26 genetic composition of two seedling lots (nursery stock and plantation) and their 27 known natural seed origin stand by means of six nuclear microsatellite loci. 28Significant reduction in genetic diversity and significant difference in genetic 29 composition of the seedling lots compared to the seed origin stand were detected. The 30 female and the total effective number of parents were quantified by means of 31 maternity assignment of seedlings and temporal changes in allele frequencies.

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Caper ( Capparis spinosa L.) is a xerophytic shrub cultivated for its flower buds and fruits, used as food and for their medicinal properties. Breeding programs and even proper taxonomic classification of the genus Capparis has been hampered so far by the lack of reliable genetic information and molecular markers. Here, we present the first genomic resource for C. spinosa , generated by transcriptomic approach and de novo assembly. The sequencing effort produced nearly 80 million clean reads assembled into 124,723 unitranscripts. Careful annotation and comparison with public databases revealed homologs to genes with a key role in important metabolic pathways linked to abiotic stress tolerance and bio-compounds production, such purine, thiamine and phenylpropanoid biosynthesis, α-linolenic acid and lipid metabolism. Additionally, a panel of genes involved in stomatal development/distribution and encoding for Stress Associated Proteins (SAPs) was also identified. We also used the transcriptomic data to uncover novel molecular markers for caper. Out of 50 SSRs tested, 14 proved polymorphic and represent the first set of SSR markers for the genus Capparis . This transcriptome will be an important contribution to future studies and breeding programs for this orphan crop, aiding to the development of improved varieties to sustain agriculture in arid conditions.