Confederate rose (Hibiscus mutabilis): https://en.wikipedia.org/wiki/Hibiscus_mutabilis
Capsules of Confederate rose plants, Maple Mountain Garden, Sumpu Castle Park, Shizuoka-city, Shizuoka, 11/24/2025
https://en.wikipedia.org/wiki/Capsule_(fruit)
https://sumpu-castlepark.com/en/; https://en.wikipedia.org/wiki/Sunpu_Castle