asteraceae, brassicaceae, caryophyllaceae, chromosome studies, malvaceae, onagraceae, papaveraceae, plantaginaceae, poaceae, polygonaceae, portulacaceae, rosaceae, species distribution, Botany, QK1-989

Chromosome numbers (2n) of 15 invasive and potentially invasive plant species from the families Asteraceae, Brassicaceae, Caryophyllaceae, Malvaceae, Onagraceae, Papaveraceae, Plantaginaceae, Poaceae, Polygonaceae, Portulacaceae, and Rosaceae are reported on the samples collected in the Republic of Altai. To determine the chromosome number (ploidy level), the method of direct counting was used. Among studied species, chromosome complements for Persicaria orientalis (2n = 22), Potentilla norvegica (2n = 42), Veronica persica (2n = 28) were first examined from Russia; for Papaver rhoeas (2n = 14) and Rumex obtusifolius (2n = 20) – from Asian part of Russia; for Bromus squarrosus (2n = 14), Cosmos bipinnatus (2n = 24), and Eriochloa villosa (2n = 54) – from Siberia. Abutilon theophrasti (2n = 42) and Lepidium densiflorum (2n = 32) were first studied from Western Siberia; Epilobium ciliatum subsp. adenocaulon (2n = 36), Portulaca oleracea (2n = 36), Spergularia rubra (2n = 36), and Xanthium strumarium (2n = 36) – from the Republic of Altai. Common distribution and the history of floristic findings of these species in the Republic of Altai are given. Previously published data on chromosome numbers from Russia are cited.