Anna Jakubska-Busse

Validation of leaf undulation traits in the taxonomy of Epipactis muelleri Godfery, 1921 (Orchidaceae, Neottieae)

Leaf undulation is used as a diagnostic feature in the taxonomy of different taxa of the Epipactis (Orchidaceae) genus. It is considered a specifically important trait, apart from the column (gynostemium) structure, in the identification of E. muelleri. However, leaf undulation is a common developmental phenomenon in various plants, including orchids, thus the main goal of the research presented was to validate the usefulness of this feature in Epipactis taxonomy. In the course of this study, the leaf structure of six Epipactis species was analyzed, i.e., E. albensis, E. atrorubens, E. helleborine, E. muelleri, E. palustris and E. purpurata. The leaf margin outline and the cellular pattern of the leaf surface, as well as the presence of papillae, were examined in detail. The results obtained showed that in all taxa analyzed, representing different groups of the Epipactis genus, leaf undulation was present. The phenomenon was related to leaf blade development and the local differential growth of leaf sectors rather than to the taxonomic position of the species. Therefore, leaf undulation studied in Helleborines does not have a diagnostic value as a non-programmed intrinsic feature and should not be applied to taxa identification. The valid trait in Epipactis classification (including E. muelleri) is the column structure.

Morphological Variability in Epipactis purpurata s. stricto (Orchidaceae) — An Analysis Based on Herbarium Material and Field Observations

A wide range of phenotypic variability in the orchid Epipactis purpurata s. stricto was found based on analysis of herbarium material and field research. Twenty-three biometric features were analysed. New diagnostically important features of gynostemium as well as of petal and sepal sizes and colours were established. Thus E. purpurata s. stricto is redescribed, clarifying the taxonomic importance of several morphological features.

The westernmost locality of Macrosciadium alatum (Apiaceae) in Europe and a new diagnostic feature of the species

A new locality of Macrosciadium alatum in the Western Bieszczady Mts. (Duszatyn, Komancza district, Sanok county) is described in this paper. The locality is currently the westernmost point of distribution of the species. As Macrosciadium alatum is an invasive species, it is advisable to monitor it cyclically in this area. A newly discovered diagnostic feature of this species, not included in descriptions of this plant so far, is conically elongated cells, i.e. papillae on the upper side of the petals. It is suggested that this feature be used in the identification of representatives of the Apiaceae family in Poland and Europe. The distribution map of the species has been updated in this work.

How does an invasive Heracleum sosnowskyi affect soil nematode communities in natural conditions

We analysed the effect of the invasive perennial plant Heracleum sosnowskyi on soil nematode communities and diversity, and plant species composition, by comparing invaded and non-invaded (control) areas in natural conditions. Invasion of H. sosnowskyi caused significant shifts in plant species composition, which subsequently modified nematode assemblages. Stress-sensitive omnivores, fungivores and root-biomass-dependent obligate plant parasites best reflected changes in soil nematode communities under the influence of H. sosnowskyi invasion. The negative effect of H. sosnowskyi was most evident on Aphelenchus , Tylencholaimus , Geocenamus , Helicotylenchus , Pratylenchus , Tylenchorhynchus and Aporcelaimellus . Our results indicate that significant changes in the herbaceous layer after H. sosnowskyi invasion in ecosystems where H. sosnowskyi eventually became dominant impacted soil nematode communities but did not affect nematode diversity. This was in contrast to the habitats where a solitary plant of H. sosnowskyi grew and no significant changes in nematode communities were observed.

Epipactis purpurata f. variegata (Orchidaceae), A New Infraspecific Taxon

A new infraspecific taxon in Orchidaceae, Epipactis purpurata f. variegata Żołubak & Jakubska-Busse f. nova, with variegated leaves, is described and illustrated from Lower Silesia, Poland.

Leaf arrangements are invalid in the taxonomy of orchid species

The selection and validation of proper distinguishing characters are of crucial importance in taxonomic revisions. The modern classifications of orchids utilize the molecular tools, but still the selection and identification of the material used in these studies is for the most part related to general species morphology. One of the vegetative characters quoted in orchid manuals is leaf arrangement. However, phyllotactic diversity and ontogenetic changeability have not been analysed in detail in reference to particular taxonomic groups. Therefore, we evaluated the usefulness of leaf arrangements in the taxonomy of the genus Epipactis Zinn, 1757. Typical leaf arrangements in shoots of this genus are described as distichous or spiral. However, in the course of field research and screening of herbarium materials, we indisputably disproved the presence of distichous phyllotaxis in the species Epipactis purpurata Sm. and confirmed the spiral Fibonacci pattern as the dominant leaf arrangement. In addition, detailed analyses revealed the presence of atypical decussate phyllotaxis in this species, as well as demonstrated the ontogenetic formation of pseudowhorls. These findings confirm ontogenetic variability and plasticity in E. purpurata. Our results are discussed in the context of their significance in delimitations of complex taxa within the genus Epipactis.

Juncus quartinianus (Juncaceae, sect. Ozophyllum): A Neglected Species from the Horn of Africa and Its Re-Description Based on Morphological SEM Studies

Juncus quartinianus (Juncaceae sect. Ozophyllum) was described by Richard in 1851 from Ethiopia. Some authors have treated this species as a synonym of J. fontanesii and others as a synonym of J. oxycarpus. Based on morphological analyses of flowers, fruit and seeds, we propose to restore J. quartinianus as a distinct species from both these taxa. Its detailed re-description and an identification key to the morphologically similar species of Juncus sect. Ozophyllum are provided.

Epipactis × subtilis (Orchidaceae), a New Hybrid between E. albensis and E. purpurata

A new natural hybrid Epipactis × subtilis Jakubska-Busse, Żołubak & Łobas, hybr. nat. nov. (Epipactis albensis × Epipactis purpurata) is described and documented from the province of Lower Silesia (SW Poland). The hybrids morphological characteristics are compared with those of the parental species.

Neotypification of Epipactis violacea f. chlorophylla Seeland (Orchidaceae)

A neotype is designated for Epipactis violacea f. chlorophylla Seeland, which is the basionym of E. purpurata f. chlorophylla (Seeland) P. Delforge, the presently accepted name of the taxon.

Shapes of leaves with parallel venation. Modelling of the Epipactis sp. (Orchidaceae) leaves with the help of a system of coupled elastic beams

Static properties of leaves with parallel venation, with particular emphasis on the genus EpipactisZinn, 1757 (Orchidaceae, Neottieae) have been modelled with coupled quasi-parallel elastic “beams.” The non-linear theory of strongly bended beams have been employed. The resulting boundary-value problem has been solved numerically with the help of the finite-difference method. Possible dislocations resulting in additional Dirac-delta like forces have been take into account. Morphological similarity of the model and real leaves has been obtained. In particular, the concentrated forces have been shown to cause undulation in the leaves.