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• Taxonomic revision of alien Ludwigia species in Hungary

  153–164

  Attila Mesterházy

  Norbert Riezing

  Róbert Vidéki

  Views:

  258

  Some tropical Ludwigia species have been planted as ornamentals in Hungarian thermal springs since the 1920s. Although they have become naturalised or even invasive in a few places, their specific identity remained generally uncertain. Our herbarium and field studies revealed that three species of alien water-primroses occur in Hungary. The most frequently planted one is Ludwigia repens, which is, however, a sporadic species in its native distribution area. We have found this species in several parts of the country. Although a few escaped and self-sustaining populations were also observed, this species has appeared to be non-invasive so far. Ludwigia grandiflora appeared in Hungary at the beginning of the 2000s. At the moment it is known from three localities, though spreading rapidly, becoming already invasive in its locality at Tata city. A similar species, L. peploides has recently been reported from two localities, where it forms small stands; the success of its naturalisation can be assessed in the future. We found no evidence for the Hungarian occurrence of L. alterniflora that had been published from Eger city. Therefore we suggest deleting this species from the current Hungarian checklist.

• Contributions to the flora of the Danube River in Komárom-Esztergom and Fejér counties (Hungary)

  157–168

  Norbert Riezing

  Views:

  266

  The present paper focuses on the aquatic and Nanocyperion vegetation of the Danube flood­plain. Most of the data show the results of the surveys in 2019 at low water levels. The Nanocyperion and aquatic vegetation of the Komárom-Esztergom County section is relatively well researched com­pared to the Fejér County section which was previously poorly known. In the last decade, two rare spe­cies – Hippuris vulgaris and Hydrocharis morsus-ranae – have disappeared between Gönyű and Neszmély (Komárom-Esztergom County). In contrast, several new invasive plants have appeared: Salvinia molesta, Myriophyllum aquaticum, Limnobium laevigatum, and Crassula helmsii (first record from Hungary). Vallisneria spiralis and Elodea canadensis were detected again after several decades. Elodea nuttallii and Azolla sp. have become more widespread and abundant than previously. New and uncommon Nanocyperion species were the native and protected Lindernia procumbens and the inva­sive Lindernia dubia. New invasive plants in the studied Danube sections were: Cyperus esculentus, Euphorbia maculata, and Eleusine indica. The native Veronica catenata and Schoenoplectus triqueter have become more wide­spread than before. Polygonum graminifolium was an interesting find of open pebble surfaces in several parts of the examined area, which has no recent records in Hungary from before 2015 (published here).