Poetic term for seaweed, often used in classical Japanese poetry and literature.
玉藻の生い茂る海辺を詠んだ和歌がある。
There is a waka poem that describes a shore overgrown with seaweed.
The derivation is uncertain; the kanji 玉 (jewel) and 藻 (seaweed) together create a poetic image of beautiful seaweed.