Drosera rotundifolia L.

Family: Droseraceae
English: Sundew
Japanese: モウセンゴケ (毛氈苔) [Mōsengoké]

The common sundew is a carnivorous plant. Sticky drops on the leaf hairs hold insects while the leaves close in (so I hear) about 20 or 30 minutes. Look for them on steep, well-lit moss-covered rock walls at all elevations where water drips constantly.

References:
新版　屋久島の植物 川原勝征,初島住彦(監修),2001：南方新社
米倉浩司・梶田忠 (2003-)　「BG Plants 和名－学名インデックス」（YList），http://ylist.info（ 2019年8月14日）