Gentiana yakushimensis Makino

Family: Gentianaceae
English: Yakushima gentian
Japanese: ヤクシマリンドウ (屋久島竜胆) [Yakushima Rindō]

To me, this distinctive flower represents Yakushima as well as any. It's natural range is limited to the sides of boulders thrusting up from the highest of Yakushima's inner mountains. The blooms are short-lived and only open when struck by direct sunshine. How can these drops of fallen sky perpetuate? Look for them in early August through early September.

References:
屋久島の植物　 川原勝征,初島住彦(監修),1995：八重岳書房
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）