Japanese name: ヒメカイウ（姫海芋） Scientific name:Calla palustris
[Overview]
A perennial 10–30 cm tall, growing in colonies in ponds and similar places within sunny wetlands.
A rhizome 1–2 cm in diameter creeps through the mud at the pond bottom.
The leaves are simple and tufted, heart-shaped, 7–14 cm in both length and width, entire, and glossy on the surface.
The leaf stalk is 10–25 cm long, and at the upper end of the sheath of the leaf stalk there is a membranous ligule 3–5 cm long.
Flower stalks 15–30 cm tall rise from the root, bearing a spadix enclosed in a white, broadly ovate to broadly elliptic spathe 4–6 cm long.
The spadix is cylindrical, 1.5–3 cm long, and has no appendage.
The flowers have no petals and are densely packed on the spadix.
The fruit is a globose berry that ripens red.
[Uses]
The rhizome is poisonous, but it apparently becomes edible once the poison is removed.
[Notes]
The alternative name Mizu-imo comes from the edible rhizomes it extends in the water.
