Leaf Morphology of the Rheophyte, Rhododendron indicum f. otakumi (Ericaceae)
2004 年 55 巻 1 号 p. 45-54
詳細
2004 年 55 巻 1 号 p. 45-54
Rhododendron indicum f. otakumi is an endemic rheophyte on Yakushima, Japan. The morphology and anatomy of the leaves of R. indicum f. otakumi and R. indicum f. indicum, its putative ancestor, were examined to determine differences between them. The leaves of f. otakumi are narrower than those of f. indicum, with leaf length to width ratios of 5.10 and 3.38, respectively. Our examination revealed that stenophylly in R. indicum f. otakumi was due to a decrease in the number of cells across the width of the leaf in both the adaxial epidermis and palisade tissues, even though the leaf cells of the epidermis and palisade tissue were larger in R. indicum f. otakumi. The heavy rainfall on Yakushima may have been a factor in the evolution of the narrow leaved form of R. indicum.
