Mangroves
Oriental mangrove / Bruguiera gymnorhiza / Ohirugi / オヒルギ
This tree grows in large colonies in mangrove forests on Amami-Oshima and other southern islands. Although it can grow taller, most of the trees here are less than 10 meters high. The rough bark is grayish-brown, and the oval leaves are dark green and pointed at the tip. The roots that protrude from the ground to absorb air are known as “knee roots.” This has given the tree its scientific name, a combination of the Greek words gymno (naked) and rhiza (root). The flowers’ calyxes vary from pink to dark red, and are split at the tip. The seeds mature while on the tree before dropping.
Oval-leaf mangrove / Kandelia obovata / Mehirugi / メヒルギ
This member of the mangrove family is found on many of Japan’s southern islands, including in the Sumiyo Mangrove Forest of Amami-Oshima. It can reach a height of 8 meters, but is usually much smaller. The bark is dark brown and the leaves are a glossy bright green. It develops buttress roots, and has a respiratory root layer around the trunk. The flowers have white, star-shaped calyxes. The seeds germinate and grow into a long pod-like shape while they are still on the tree, dropping to the ground when mature. They are often carried great distances by the tides, putting down roots and flourishing when they reach a favorable location.