The Orchidaceae family is a diverse family of flowering plants that occur naturally in most parts of the world. However, fungal communities inhabiting different parts of orchids are not sufficiently described. The aim of the study was to conduct a mycological evaluation of Epipactis helleborine and E. purpurata (Orchidaceae), which grow naturally in Lower Silesia (SW Poland), by identifying the species composition of the culturable micromycetes fungi on the surfaces of the plants and from the inner layers of the tissues. Fungi were identified based on a phenotypic and genotypic analysis. To our knowledge, this is the first such analysis. This study showed that more species of micromycetes were cultured from E. helleborine compared with E. purpurata. The flowering plants of E. helleborine were inhabited by the largest number of culturable fungal species (13 species), and the fewest species were isolated from the flowering plants of E. purpurata (eight species). Some of these fungal species may be pathogens of the plants. The surface tissues of the orchids were mainly inhabited by Mucor moelleri and/or Penicillium biourgeianum. The inner layers of these plants were the most colonized by Alternaria tenuissima and/or Arthrinium arundinis and/or Fusarium sporotrichioides. The relative dominance of these fungal species depended mainly on the development phase of the plants.

Epipactis greuteri is an obligate autogamous orchid species. Due to large differences in the interpretation of the diagnosis of this species, it is often mistakenly identified by botanists, which results in erroneous information provided in the literature about its distribution in Europe. In the present paper we review its description, including flower details, gynostemium features, and papillae morphology and compare it to E. helleborine, with which it is often confused. Based on thorough study of herbarium material (including holotype and isotype) and field research in Greece, Romania, and Poland, we confirm that gynostemium of E. greuteri has strongly reduced clinandrium and does not produce viscidium. We also discuss taxonomic treatment of E. preinensis and E. flaminia, two recently described taxa related to E. greuteri. The results of genetic analyses, as well as the range of phenotypic variability of E. greuteri individuals from various regions of Europe were presented and discussed. The analysis based on the ITS (internal transcribed spacer) nuclear marker showed no differences among E. helleborine, E. purpurata, E. albensis, and E. greuteri, which probably indicates their close relationship. Based on the analysis of plastid regions, six haplotypes were detected in all investigated samples. An exhaustive description of morphological features of E. greuteri is provided.

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.

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