Aosa (English spelling) Sea lettuce

A green algae belonging to the Ulva family. It has a broad, flattened green thallus, with two layers of cells in cross section. It is also called "anaaosa" ("ulva perforata"), as the thallus is commonly found with many holes. However, since coastal seawater has become severely polluted, ribbon ulva, which has a body shape divided into many lobes, has proliferated, causing damage to fishing industries. Other species in the Ulva genus include button ulva, amia ulva, and perforated ulva. It is a seaweed with a wide adaptability, and species of the genus Ulva can be found on any coast. Its leaves are tough and unsuitable for eating, so it is often used as livestock feed.

[Moriaki Shinzaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

緑藻植物、アオサ科の海藻。緑色で幅広い扁平(へんぺい)葉状体をなし、縦断面は細胞が2層に並ぶ。穴あきの多い葉体が普遍的であったため、アナアオサともいう。しかし、沿岸海水の汚染がひどくなってからは、数多くの裂片に分かれる体形のリボンアオサが繁殖し、漁業被害なども出てきている。そのほか、ボタンアオサ、アミアオサ、ヤブレグサなどがアオサ属に含まれる。適応性の広い海藻で、どこの海岸でもアオサ属のいずれかの種が分布する。葉質が堅く、食用には不適で、家畜飼料に利用される場合が多い。

［新崎盛敏］

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