Ardisia crispa (Thunb.) A.DC.

Family: Primulaceae
Japanese: カラタチバナ (唐橘) [Karatachibana]

In the series of plants with old names for coinage—10,000 ryo, 1,000 ryo, 100 ryo, etc.—this is 100 ryo. Easily overlooked since it is only a small shrub at best and usually grows on top of stumps or rocks, it is nevertheless pretty with small pink-tinged flowers followed by bright red berries.

References:
e-yakusou.com Referenced 2016-10-14 from http://www.e-yakusou.com/sou02/soumm289.htm .
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）