A lucidophyllous forest in the upper reaches of the Ayaminami River, Miyazaki Prefecture, was studied in order to clarif ydistributio nof the lucidophyllous elements and species richness along the altitudina lgradient. We studied 59 plots of 225m2 from 180m to 830m above sea level .We recognized 17 species groups by the similarity of each distributional pattern of frequency(%) of occurrence and mean coverage (%) of each species along the altitudina lgradient .Species groups of 1 to 7 were mainly distributed in the low mountainous areas. Especially species group 1, which was composed of Randia cochinchinensis, Piper kadzura, Ardisia pusilla, Uncaria rhychophylla and others, was restricted to the low areas from 170m to 200m. Species groups 9 to 15 were dominantly distributed in the upper mountainous areas. In the middle mountainous area, species group 16 was distributed. As a result of comparison of mean temperature of the coldest month (°C) at the upper limit of each lucidophyllous element on Mt. Kurinodake with Ayaminami River, there is littl edifference in the critica lvalue of each lucidophyllous element between the two regions. Species richness (number of species) per 225m2 ranged from 30 to 68 and decreased abruptly from low to high altitude. There were 155 species of lucidophyllous elements in the study plots in the upper reaches of the Ayaminami River. This number of species was very high in comparison with the number of species on Mt. Kurinodake and others.
