Folia biologica et geologica

Epipactis × schmalhausenii K. Richt. (Orchidaceae), a newly identified hybrid in Slovenian flora

Amadej Trnkoczy — 2025-07-08

This study analyzes nine specimens of the genus Epipactis from the Orchidaceae family and classifies them as Epipactis × schmalhausenii K. Richt (Epipactis atrorubens (Hoffm. ex Bernh.) Besser × Epipactis helleborine (L.) Crantz). The work provides the first detailed description of this hybrid in Slovenia. The plants were examined using the hybrid index (HI) method. We analyzed six to ten morphological plant characteristics. In addition to the traits summarized from the literature, two new characteristics related to the proportions of the flower labellum were analyzed from digital photographs and included in the study. Both of these showed high discriminatory power between the parental species. We modified the classical definition of the HI to no longer depend on the number of traits used in the analysis. The adopted trait descriptions of typical parental species were compared to six standard works on Orchidaceae. We did not observe any apparent contradictions, but the descriptions of some characteristics are somewhat inconsistent, which probably indicates their very high intraspecies variability. A brief assessment of potential geographical, site-related, and temporal barriers to hybridization between the two parental species in Slovenia revealed that none exist. The hybrid is likely quite common in Slovenia and has been overlooked until now, probably due to its substantial phenotypic diversity.

Characteristics of wood increments in stem and branches of olive trees (Olea europaea L.)

Jožica Gričar — 2025-07-08

Olive (Olea europaea L.) is an economically very important evergreen cultivated plant, but very little is known about its wood structure in the different tree parts, which is crucial for the long-term tree survival. Here, we compared the characteristics of xylem increments in the stem and branches of the olive trees in Dekani in 2016. We analyzed the conducting elements in the wood (vessels) in individual thirds of the xylem increments. For this purpose, xylem samples were taken after the end of the growing season of 2016 and histometric analyzes of the xylem tissue were performed using a light microscope and an image analysis system. The width of the xylem increments and the vessel characteristics differed in the stem and branches of the olive trees. The increments were about 54 % narrower in the branches than in the stem, and the vessel areas were between 25 % (first third) and 34 % (last third) smaller. Vessel areas were comparable in the first and second thirds of the xylem increment, while it was significantly smaller in the last third, on average by 17.6 % in the stem and 25.4 % in the branches. In all thirds of the xylem increments, we observed a negative relationship between average vessel area and vessel density. In the stem and branches of olive trees, this was reflected in comparable values of hydraulic conductivity in all xylem thirds. Narrower conducting elements in olive branches, as a result of hormonal regulation, are consistent with the universal positive relationship between vessel size and distance from the apex and are associated with higher tension of the water columns the vessels in the branches compared to the stem. The different structure of the xylem increments in the stem and branches indicates the different role of this tissue in different parts of the olive trees.

Some characteristics of vegetation and flora of the Beka Landscape Park and its close surroundings (southwestern Slovenia)

Igor Dakskobler — 2025-07-08

In the Beka Landscape Park (the spring and central part of the Glinščica valley, both banks of the gorge of Griža, the valley of Korošca near Beka-Ocizla caves) and its immediate surroundings (meadows by Beka and Ocizla) we determined eleven forest communities at the rank of association, with dominant Quercus petarea, Q. pubescens, Ostrya carpinifolia, Carpinus betulus, Fagus sylvatica, Alnus glutinosa, Tilia platyphyllos, Acer pseudoplatanus and (or) Pinus nigra. The recorded grasslands can be classified into at least six syntaxa at the rank of association. We partly investigated also the vegetation of screes, rock crevices, shrubs, hedges, ponds and abandoned fields. In the researched area we recorded approximately 730 taxa of vascular plants, including 49 protected, 48 Red List, and 30 alien species. Some of the identified plant communities belong to Natura 2000 habitat types, among them Eastern sub-mediterranean dry grasslands (Scorzoneretalia villosae) and Illyrian Fagus sylvatica forests (Aremonio-Fagion). At Ocizla and Beka are localities of Himantoglossum adriaticum, a species of Community interest.