A study of the phytochemical and molecular characteristics of ten Micromeria and six Clinopodium taxa (family Lamiaceae) distributed in the Balkan Peninsula was carried out. The phytochemicals detected in essential oils by gas chromatography, mass spectrometry, and molecular data amplified fragment length polymorphism were used to study the taxonomic relationships among the taxa and the correlations between phytochemical and molecular data. STRUCTURE analysis revealed three genetic groups, while Bayesian Analysis of Population Structure grouped the studied taxa into 11 clusters nested in the groups obtained by STRUCTURE. Principal components analysis performed with the 21 most represented compounds in the essential oils yielded results that were partly consistent with those obtained by STRUCTURE and neighbour-joining analyses. However, their geographic distributions did not support the genetic grouping of the studied taxa and populations. The Mantel test showed a significant correlation between the phytochemical and genetic data (r = 0.421, p < 0.001). Genetic distance explained 17.8% of the phytochemical distance between populations. The current taxonomic position of several of the studied taxa is yet to be satisfactorily resolved, and further studies are needed. Such future research should include nuclear and plastid DNA sequences from a larger sample of populations and individuals.

A study of the trichomes types and distribution and pollen morphology was carried out in nine Micromeria taxa (M. cristata ssp. cristata, M. cristata ssp. kosaninii, M. croatica, M. graeca ssp. graeca, M. graeca ssp. fruticulosa, M. juliana, M. kerneri, M. longipedunculata and M. microphylla) and five closely related Clinopodium species (C. dalmaticum, C. frivaldszkyanum, C. pulegium, C. serpyllifolium and C. thymifolium) from the Lamiaceae family of the Balkan Peninsula. By scanning electron microscope, non-glandular trichomes, peltate and capitate trichomes were observed on the calyx, leaves and stem of the studied species. Two subtypes of capitate trichomes were observed in Micromeria species: subtype 1 (consisting of a basal epidermal cell and an elliptically shaped head cell) and subtype 2 (consisting of a basal epidermal cell, two to three stalk cells and a round head cell). In Clinopodium species, three types of capitate trichomes were observed: subtype 1, subtype 3 (consisting of a basal epidermal cell, a short peduncle cell, and a single round head cell), and subtype 4 (consisting of a basal epidermal cell, a stalk cell, and an elongated head cell). These results support the recent transfer of Micromeria species from the section Pseudomelissa to the genus Clinopodium.

Owing to the difficulties in measuring daily reference potential evapotranspiration, its estimation by means of the ASCE Penman-Monteith approach and various other empirical equations that are less demanding in terms of input data is favoured for various applications in vegetation science and climatology. This study presents the development of a Visual Basic software that can be used for the estimation of the daily ${\mathrm{PET}}_{\mathrm{ref}}$ by means of the standardized ASCE Penman-Monteith equation for both short (clipped grass) and tall (full-cover alfalfa) crops and thirteen additional empirical equations. Statistical measures of goodness of fit are also calculated to make it easier for users to compare and detect the empirical equations that have the minimum bias of estimation against the ASCE Penman-Monteith equation.

The definition of typical species inventories of the 92/43/EEC Directive habitat types is a valuable information for the optimization of the conservation status assessment. Habitat-specific assessment protocols and predefined local inventories of typical species provide a method for a relatively fast and accurate assessment of the criterion “structures and functions”. Habitat types are often defined and described on the basis of a phytosociological description of vegetation units, mainly at the syntaxonomical level of alliance. Therefore, the definition of typical species inventories can be based on phytosociological approaches. Within this concept we surveyed the vegetation of a NATURA 2000 Special Area of Conservation in northern Greece in order to optimize and downscale the existing region-wide inventories of typical species. In total, we sampled 164 relevés in beech and in thermophilous deciduous broadleaved forests. The relevés were assigned to vegetation units and habitat types using numerical approaches and their differential and constant taxa were defined. We used these taxa to draw up the optimized, site-specific inventories of typical species for seven habitat types of community interest and one habitat type of national interest.

Vegetation succession is a key element for research studying biodiversity losses, effects of climatic change on ecosystems, invasive species and restoration of ecosystems in which human activities have shifted their natural or semi-natural vegetation. Surrogate variables like Pignatti's bioindicator values or dissimilarity indices can provide further insights regarding succession trajectories aggregating the combined effects of changes in the cover/abundance of taxa. The land-use abandonment in an area in the estuary of the River Aliakmon, N. Greece, provides an opportunity to study medium-term rates and patterns during the first twelve years of vegetation succession. Cluster and time-series analyses of turnover rates, Sørensen's dissimilarity index and Pignatti's bioindicator values revealed clear differences in succession patterns and rates among permanent plots. Succession rates and patterns in the study area were found to be dominated by two ecological factors. On the one hand, availability of fresh water, assumed by the proximity to the river, allows the fast growing Populus alba to develop a forest canopy that radically alters the shading environment which, in its turn, controls succession trajectories. Increased soil salinity on the other hand, allows salt-tolerant taxa to be quickly established, and defines the species inventory on these sites as early as the first years of succession.