threeleaf arrowhead (Sagittaria trifolia)
A perennial aquatic plant with arrow-shaped leaves, native to East Asia. The corms are edible and known as クワイ.
Threeleaf arrowhead is growing in the corner of the rice paddy.
オモダカの葉は矢じりのような形をしている。
The leaves of the threeleaf arrowhead are shaped like arrowheads.
クワイ refers specifically to the edible corm of the threeleaf arrowhead (Sagittaria trifolia var. edulis), often eaten in Japanese cuisine, while オモダカ is the general name for the plant.
Pyrrosia tricuspis (species of felt fern)
Usually written in katakana for this plant name; usually written in kana.
Kanji form; rarely used in practice.
Hiragana spelling, also common.
Alternate kanji form; very rare.
The name オモダカ is thought to derive from the shape of the leaves resembling a raised face (面高), but the exact origin is uncertain.