小山・ファン・内田・中原-坪田・坪田 2022

小山ほか（2022）

• 小山克輝・ファン=クイン=チ・内田真治・中原-坪田美保・坪田博美. 2022. 広島県のモロコシソウの生育状況について―2022年時点の状況―. Hikobia 18: 265-272.

Abstract

Lysimachia sikokiana Miq. (Primulaceae) is a rare plant species distributed in the Seto Inland Sea area, SW Japan, and has been listed as an RDB species of Hiroshima Prefecture. Located in the south of Hiroshima, Miyajima Island is an important geographic location because it is near the northern limit of L. sikokiana. Here we report the current growing condition of this species on Miyajima Island and provide the basic information for its conservation. The height of L. sikokiana was smaller than plants growing in other places. The reasons for this might include environmental change in addition to the Wright effect and the distribution being close to its northern limit. Furthermore, the local population is disappearing, and the existing population showed a decrease in both population size and plant growth. The results suggested that closure of the forest canopy gaps has been associated with a decrease in light intensity and water content on forest floor, altering the favorable environment of L. sikokiana. Natural disturbances, such as tree fall caused by typhoons that create canopy gaps, have not occurred in recent years, and no canopy gaps have been made in places where L. sikokiana is present. This study sheds light on the status of the local population of L. sikokiana on Miyajima Island and demonstrates the need for ex-situ conservation.

ノート

• 広島県のモロコシソウの現状について報告した．