Allium virgunculae F.Maek. et Kitam. var. yakushimense M.Hotta

Family: Amaryllidaceae
Japanese: ヤクシマイトラッキョウ [Yakushima itorakkyou]

I never imagined wild onions atop mountains! This allium has been identified rather recently has flowers that seema bit more dainty and lavender in color compaired to the A. acrostemon along the coasts.

References:
Hotta, M. Taxonomical notes on plants in southern Japan IV. The Allium thunbergii group (Liliaceae) istributed in southern Kyushu and Ryukyu Islands Acta Phytotaxonomica et Geobotanica 49(1): 66. 1998
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13日）