We have as our starting point a genus with very well-known species, but with a highly debated systematics and unexploited economic potential. Polygonum is a large and cosmopolitan genus (the online taxonomic database, Plants of the World Online recognizes 173 species, but other authors, e.g. DONG et al., 2014, in IDOUDI et al., 2024 consider about 300 species), with very common plant species in Romania's flora, known as “knotweeds”. The systematics of the genus Polygonum is controversial and still unresolved, that's why several species have been reclassified and moved to the genera Persicaria, Bistorta, Fagopyrum, Fallopia, Reynoutria, Koenigia. CIOCÂRLAN (2009) presents 25 spontaneous and cultivated species from our country. The cultivated ones are Fallopia aubertii (L. Henry) Holub (Polygonum aubertii Louis Henri), Persicaria orientalis (L.) Spach (Polygonum orientale L.), Reynoutria japonica Houtt. (Polygonum cuspidatum Sieb. et Zucc.) and Reynoutria sachalinensis Nakai (Polygonum sachalinense Fr. Schmidt). The last two species escaped from culture and became subspontaneous and very aggressive as invasives. The spontaneous species grow in ponds and marshes, in ditches and canals, in humid forests or some are segetal and ruderal. We are discussing here those that belong to the first ecological category. That's why we have chosen the following 7 species encountered in humid areas: Persicaria amphibia (L.) Delarbre (Polygonum amphibium L.), Persicaria hydropiper (L.) Delarbre (Polygonum hydropiper L.), Persicaria lapathifolia (L.) Delarbre (Polygonum lapathyfolium L.), Persicaria minor (Huds.) Opiz (Polygonum minus Hudson), Persicaria mitis (Schrank) Holub (Polygonum mite Schrank), Persicaria maculosa Gray (Polygonum persicaria L.), Reynoutria japonica Houtt. (Polygonum cuspidatum Sieb. et Zucc.). Our chorological data is corroborated with that collected in this region by TÖKES, SORAN, BOŞCAIU, GRIGORE, VICOL, OPREA et al., ARVAT, COSTE, DRĂGULESCU and other authors (from 1905 until now). We have taken into account the ecological differences, their participation in the vegetation and we draw attention to the spread of one of the very invasive species, Reynoutria japonica Houtt. We would like to emphasize that we look at them not only from a botanical and ecological point of view, but also from the perspective of their pharmaceutical potential, because some species contain phytochemical compounds.

knotweed, humid area, Romanian Banat, invasive plants, economic potential

biology

Presentation: poster