Morphological variation in 52 populations of Nuphar japonica DC., N. subintegerrima (Casp.) Makino, N. oguraensis Miki and unidentified intermediate plants were investigated during a revision of Nuphar (Nymphaeaceae) in Japan. The phenogram of cluster analysis based on 15 morphological characters revealed five cluster groups (A〜E). Clusters A, C and E had some remarkable characters and corresponded well to the description of N. japonica, N. oguraensis and N. subintegerrima sensu stricto, respectively. In contrast, Clusters B and D showed intermediate values in most of their characters. It was concluded that the intermediate plants, which usually had been identified as N. subintegerrima, were not conspecific with N. subintegerrima s. s. and that there were two different intermediate groups in central to western Japan. Morphological relationships suggested that the two intermediate groups were of hybrid origin between N. japonica and N. oguraensis and between N. japonica and N. subintegerrima, respectively. Results from the present study proved that populations of N. subintegerrima s. s. are limited in number and distribution, and that the species is one of the most endangered plants in Japan.
抄録全体を表示