01 / Suizenjinori
The blue-green alga Suizenjinori is thoughtto grow wild in the Kogane River.

A dark-green blue-green alga that grows sunk on the beds of spring-fed pools. Fukuoka's Red Data Book says it has been confirmed only at Kami-Ezuko (上江津湖, Kumamoto) and the Kogane River (黄金川, Asakura), and that the Kogane River is thought to be the only place it grows wild. The nationally designated natural monument is Ezuko (江津湖) in Kumamoto; in the Kogane River, cultivation helps sustain it.
- Confirmed only at Kami-Ezuko and the Kogane River (Fukuoka RDB 2024)
- The Kogane River is thought to be the only place it grows wild (Fukuoka RDB 2024)
- Two operators cultivate it, sustaining its growth (Fukuoka RDB 2024)