noun
spiny water nymph; spiny naiad; holly-leaved naiad
An aquatic plant, Najas marina, with spiny leaves. The name is usually written in katakana.
イバラモは湖や池に生える水草です。
The spiny water nymph is an aquatic plant that grows in lakes and ponds.
イバラモの葉には小さなとげがあります。
The leaves of the spiny water nymph have small spines.
The name likely derives from 茨 (ibara, 'thorn') and 藻 (mo, 'algae/water plant'), referring to the plant's spiny leaves. The exact historical derivation is uncertain.