Distribution and morphological description of Ilex rugosa Fr. Schmidt from eight Japanese mountains

This paper describes th distribution and morphology of Ilex rugosa Fr. Schmidt, an evergreen shrub native to Japan. The aims of this investigation were to determine if Ilex rugosa specimens from eight Japanese mountains could be segregated into the varieties accepted by Yamazaki (1987; 1989) and wether populations of I. rugosa differ morphologically based on mountain of origin, altitude, or plant gender (male or female). The specimens were found on seven of eight investigated mountains in Hokkaido and Honshu. There was no statistically significant evidence for segregating the populations of I. rugosa from different mountains on the basis of leaf length or width. Internode length differed significantly from mountain to mountain. Leaf width decreased significantly with increasing altitude; leaf length displayed no such pattern. Internode length varied more in male than in female plants, but no other morphological differences between male and female I. rugosa were found. We also examined growth habits, lateral shoot rooting ability, and leaf colour of the plants in the study area.These characteristics varied little between populations. Plants of I. rugosa grown for four years in Denmark showed significantly larger leaves and internode length than plants in Japan.