Tricyrtis nana Yatabe

Family: Liliaceae
English: Japanese toad-lily sp.
Japanese: チャボホトトギス (矮鶏杜鵑草) [Chabo Hototogisu]

At the end of summer, you'd be lucky to pass one of these short lilies in bloom. The plants are common enough, but the flowers only last for a day.

References:
九州野山の花 片野田逸朗,2004：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）