noun
Ptilophora subcostata (species of red alga)
A species of red alga. The name is typically written in katakana as ヒラクサ.
ヒラクサは紅藻の一種で、日本近海で見られる。
ヒラクサ is a type of red alga found in the seas around Japan.
The name likely derives from 平 (ひら, 'flat') and 草 (くさ, 'grass' or 'plant'), referring to its flat, plant-like appearance. The exact derivation is uncertain.