"Munin-tsutsuji" (Rhododendron boninense) belongs to Ericaceae (the Azalea family). It is a small evergreen tree that is endemic to Japan and grows only on Chichijima Island in the Ogasawara Islands. It grows in mountainous areas and is 2 to 3 m tall. The branches and petioles are densely covered with long, stiff, light brown hairs. The leaves are broadly lanceolate, 3.5 to 6 cm long, and somewhat leathery. Two to three white flowers bloom from a single flower bud at the tip of a branch, mainly from late April to mid-May.