In this study we report the occurrence data of 14 fern species from the area of the Danube–Tisza Interfluve and the Tiszántúl (Great Hungarian Plain). All data have been collected from sec­ondary habitats, such as buildings and man-made structures, pine plantations and canals. We pre­sent new data on seven protected and one alien fern species (Azolla filiculoides). Seven and six species were found together on the brick walls of old buildings near the railway stations in Bácsalmás and Baja, respectively. The new occurrences of Gymnocarpium robertianum, Pteridium aquilinum, Asplenium adiantum-nigrum and Polypodium vulgare have great importance from a floristic point of view. The latter two species were recorded both in pine plantations and on brick walls.

Railways are important introduction and dispersal corridors for plant species. The first establishment and spread of many alien plant species in Hungary can be linked to railways nowadays. Sabulina tenuifolia (L.) Rchb. is a sub-Atlantic–sub-Mediterranean–Western-Asian plant, which was not previously known from the flora of Hungary, but a small population of the species was found in Budapest, at the Rákospalota-Újpest railway station. The plant was probably introduced as a stowaway of rail transport and its further spread along railways is expected. The inclusion of the species in the Hungarian plant identification key has been published in the article.

New or recently confirmed localities of more than 50 rare or poorly known taxa (including 10 ferns) are presented from the territory of Budapest and adjacent territories. Some of those records are new for the spontaneous flora of particular territories, specifically: Anthericum liliago (Szentendre Island), Artemisia alba (Tétény Highland), Cerastium lucorum (Buda Mts, Börzsöny), Epipactis albensis (Budapest, Pilis), E. futakii (Börzsöny), E. moravica (Börzsöny, Visegrád Mts), Hippophae rhamnoides (Szentendre Island), Myosotis discolor (Börzsöny). The new localities of Cnidium dubium, Platanthera chlorantha, Spiranthes spiralis, Sternbergia colchiciflora, Veronica jacquinii and Viola stagnina are also noteworthy. Some species are discussed in more detail in relation to their former Hungarian literature records.

This paper presents new floristic data from the Putnok Hills (Northern Hungary), collected between 2022 and 2024. We found new localities of several taxa (Gymnocarpium dryopteris, Polystichum aculeatum, Dryopteris carthusiana, D. dilatata, Lychnis coronaria, Dianthus deltoides, D. collinus, Pulsatilla grandis, Hesperis sylvestris, Potentilla rupestris, Chamaecytisus albus, Lathyrus nissolia, Lathyrus palustris, Linum flavum, L. tenuifolium, Polygala major, Gentiana cruciate, Phlomis tuberosa, Pseudolysimachion longifolium, Inula helenium, Jurinea mollis, Cen­taurea triumfettii, Scorzonera purpurea, Sonchus palustris, Ornithogalum brevistylum, Scilla kladnii, Iris sibirica, Iris aphylla subsp. hungarica, Stipa pulcherrima, Cephalanthera damasonium, Neottia nidus-avis, Platanthera bifolia, Gymnadenia conopsea, Orchis morio, O. tridentata, O. ustulate, O. purpurea, O. ele­gans) that are legally protected in Hungary. We also recorded native and archeophyte weeds (Salsola kali, Silene dichotoma, Ranunculus arvensis, Bunias orientalis, Diplotaxis muralis, Vicia pannonica, Euphorbia exigua, E. falcata, Androsace elongata, Ajuga chamaepitys, Sherardia arvensis, Bromus secalinus), spreading aliens (Phytolacca ameri­cana, Mahonia aquifolium, Oxalis dilleniid, Abutilon theophrasti, Asclepias syriaca, Juncus tenuis, Elymus elongatus, Panicum dichotomiflorum) and escapees (Aquilegia vulgaris, Trifolium incarnatum, Foenicu­lum vulgare, Primula vulgaris, Lonicera caprifolium). This article contains data on 144 species, 8 of which are new to the flora of the Tornense region (Phytolacca americana, Mespilus germanica, Rhinanthus ×hungaricus, Orobanche alba subsp. major, Dipsacus ×fallax, Filago vulgaris s. str., Rudbeckia hirta, Bolboschoenus laticarpus) and 8 to the Putnok Hills (Polystichum aculeatum, Ranunculus tri­chophyllus, Diplotaxis muralis, Lathyrus palustris, Lonicera caprifolium, Crepis pulchra, Allium rotundum, Lolium multiflorum).

Revision of genus Digitaria in BP Herbarium Carpato-Pannonicum collection helped to discover the historical occurrence of Digitaria ciliaris (Retz.) Koeler from Győr, in the area of an old cotton and wool processing and textile factory. However, it has been proved that the previously publis­hed Hungarian records of the species are all wrong, as the Digitaria-keys of Hungarian herbals misin­terpreted the taxon, mainly as a synonym of D. sanguinalis subsp. pectiniformis. The herbarium survey confirmed that D. sanguinalis is the most common taxon in Hungary. D. sanguinalis subsp. pectiniformis is also widespread, but probably somewhat under-mapped. Probably not native to Hungary, most pro­bably an archeophyte taxon. Specimens have been collected from disturbed habitats associated to railways and from xerothermic vineyard areas for over a hundred years. D. ischaemum is certainly native to the region, with a recognisable natural distribution pattern, and is found mainly in the sandy and gravelly soils of the lowland and hilly areas of the country. This species has recently become more common in urban areas across the country with the recent spread of sand-lined pavements. D. ciliaris of tropical/subtropical origin is a casual alien species that was formerly present in the Hungarian flora.

In this paper, we present the new occurrence of two grass species previously unknown in the flora of Hungary and one grass species for which we have only one historical record. Panicum schinzii Hack. is an annual species from South Africa, Paspalum dilatatum Poir. is a perennial species originating from South America, and Phalaris aquatica L. is also a perennial taxon native to the Mediterranean. The only well-developed individual of Panicum schinzii was found on a gravel reef of the Rába river in Western Hungary, while the two newly observed perennial grass species appeared in the Great Hungarian Plain: a single individual of Paspalum dilatatum was observed in a suburban environment on the southern edge of the town of Soltvadkert, while a small population of Phalaris aquatica occurs along a highway near Szeged. In this paper, we describe the European dis­tribution and habitat preference of these three species, we assess their invasion potential and we fit them into the Hungarian dichotomous key of vascular plants. Although we cannot state with certainty that the specimens of Panicum schinzii, Paspalum dilatatum and Phalaris aquatica we report here are the first ones that have ever appeared in Hungary, but their localities and the numbers of individuals suggest that they have entered the country very recently. The annual Panicum schinzii certainly arrived to Hungary naturally by the river Rába, while the perennial Paspalum dilatatum and Phalaris aquatica are more likely to have been introduced by human activities, but both inadvertently. Paspalum dilata­tum arrived to its site near Soltvadkert by accident, in the form of propagules in some intentionally sown seed mixture. The fact that all three species are considered in some countries to be invasive or at least problematic species is a cause for concern.

This article summarizes the recent occurrences of taxa of the C. brutia complex in Hungary. Formerly, C. hamulata was known from Hungary based on a specimen of uncertain origin from Vas County. The first confirmed record of the species date back to 2014, since then it has been found from from a total of 4 localities in streams in Western Transdanubia and along the Danube. The first detec­tion of C. brutia subsp. brutia was in 2016 in the Kunkápolnás marsh of the Hortobágy region, and since then the subspecies has been spreading in the area. The subsp. naftolsky was found in 2024 in a terres­trial form in a saltwater marsh in the Dél-Tiszántúl region. While C. hamulata is probably a native member of the Hungarian flora, the two subspecies of C. brutia may have colonised more recently, probably introduced by birds. Their colonisation may be related to the ongoing climate change, which has resulted in the introduction of plants from the Mediterranean region, often by natural means.

Based on the data collected between 2015 and 2023, we present a detailed account of the occurrences and current distribution of Viscum album subsp. austriacum in Hungary. We present its fre­quency and abundance, and also examine the factors influencing its distribution and prevalence. The taxon is generally widespread in the western half of Western Transdanubia, where it is a characteristic (and partially native) element of the mixed pine forests of the Vendvidék, Felső-Őrség, Kőszeg Hills, and the Pinka Plain. Its occurrence has been confirmed in almost all (older) Scots pine and black pine stands of the Sopron Hills, where it has become a mass pest in several locations. Based on our studies, the current distri­bution of the taxon in Southwestern Transdanubia follows the border of the native distribution of Scots pine, but in the Kemeneshát and the Sopron–Vas Plain, the regional boundary extends 10–25 km beyond it. The frequency of pine mistletoe within the subcompartments was highest in mixed coniferous stands. We also recorded a mass infection that played a significant role in the degradation of the stands. The notable increase in the number of occurrences can be explained by the significant under-mapping of the taxon to date, as well as its documented spread throughout Europe. It is also assumed to be linked to the increasing­ly unfavorable health status of coniferous forests in Hungary. This process may be facilitat­ed by the fact that the resistance of Scots pine forests in both hilly and lowland regions has significantly declined due to the increasing length and frequency of drought periods. Compared to previous years, forest stands in weakened condition are more susceptible to infections by pathogenic organisms, such as mistletoe.

The present study discusses the community relations of the oak-ash-elm woodlands (Fraxino pannonicae-Ulmetum Soó in Aszód 1935 corr. Soó 1963) of the Middle-Tisza region based on 20 coenological recordings. This is an azonal association moderately influenced by groundwater. Its stands represent an impoverished form compared with the woodlands of the Upper-Tisza region. How­ever, its noteworthy species include the following: Acer platanoides, A. pseudoplatanus, A. tataricum, Aegopodium podagraria, Arum orientale, Carduus crispus, Carex remota, C. sylvatica, Carpinus betulus, Cephalanthera longifolia, Cerasus avium, Corydalis cava, Dryopteris carthusiana, D. filix-mas, Elymus caninus, Epipactis helleborine agg., Fagus sylvatica, Gagea lutea, Hedera helix, Fraxinus angustifolia ssp. danubialis, Melica altissima, Moehringia trinervia, Myosotis sparsiflora, Neottia nidus-avis, Ornithogalum brevistylum, Padus avium, Platanthera bifolia, Ranunculus auricomus, Ribes rubrum, Stachys sylvatica, Tilia platyphyllos, T. tomentosa, Ulmus laevis, Viburnum opulus, Viola reichenbachiana stb. 

Since 1988, open stands of Menyanthes trifoliata have disappeared, communities of Carex rostrata have declined, and the Sphagnum-dominated willow carr has expanded. The mire’s central asso­ciations include Caricetum rostratae, Salici cinereae–Sphagnetum recurvi sphagnetosum squar­rosi, and Calamagrosti–Salicetum cinereae. In the mainly nudum lagg zone, the following communities occur: Biden­ti–Polygonetum hydropiperis, Bidenti–Polygonetum hydropiperis urticetosum dioicae, Cari­cetum acutifor­mis, Juncetum effusi, Glycerietum maximae, and a community dominated by Poa nemora­lis. We recorded 77 vascular plant species, 62 of which were new to the site. Rare species have declined in number: Menyant­hes trifoliata and Cicuta virosa are now absent, and of the former eight Sphagnum species, only Sphagnum squarrosum remains. The original Salici cinereae–Sphagnetum recurvi sphagne­tosum recurvi subassociati­on transitioned into Salici cinereae–Sphagnetum recurvi sphagnetosum squar­rosi after the mire remained completely dry and peat-moss-free for several years around 2000. Central communities reflect a cool, moderately acidic, oligotrophic environment with low pH and conductivity. In contrast, lagg vegetation indicates warmer, nutrient-rich, less acidic conditions. The mire’s most valuable zone is its central, Sphag­num-rich area, whose preservation depends on a natural water supply maintained by continuous forest cover in the catchment and stable or reduced large game populations.