Alien species expand their distribution by transportation network development. Hybridization between alien species Rumex obtusifolius and closely related native vulnerable species R. longifolius was examined in a mountain tourist destination in central Japan. The three taxa were morphologically identified in the field. Stem height and leaf area were greater in R. longifolius than R. obtusifoliu...

A new epoxynaphthoquinol derivative, 3-acetyl-2-methyl-1, 5-dihydroxy-2,3-epoxynaphthoquinol (I), was isolated from the root of Rumex japonicus. The structure was elucidated by high field 1D and 2D NMR techniques.