noun
zygnema; freshwater filamentous green algae (genus Zygnema)
A genus of filamentous green algae found in freshwater. The term is a biological taxon name, typically written in katakana.
池でホシミドロの群体を見つけた。
I found a colony of Zygnema in the pond.
ホシミドロは淡水域に広く分布する藻類の一種だ。
Zygnema is a type of alga widely distributed in freshwater environments.
The Japanese name ホシミドロ is a direct translation of the genus name Zygnema, likely combining 星 (star) and 味泥 (mud with taste?), but the exact derivation is uncertain. The katakana form is standard for scientific names.