Japanese name: デンジソウ（田字草） Scientific name:Marsilea quadrifolia
[Overview]
A summer-green aquatic fern found in rice paddies, ponds and marshes.
It often grows in colonies.
The rhizome creeps for a long distance through the mud at the bottom of the water.
The leaves float on the water surface, with 4 leaflets arranged in a cross; the leaflets are fan-shaped triangles.
The petiole is 10–15 cm long.
The sporocarps are oval, about 0.5 cm long, and are borne 1–3 on a short branch arising a little above the base of the petiole.
[Uses]
The whole plant is used medicinally as a substitute for fuhyo.
[Cultivation]
Propagate by division.
Grow it in a sunny place.
Paddy soil is suitable, but akadama soil (red granular clay soil) is also fine.
For potted plants, submerge the whole pot in water and keep the base of the plant always under water.
For fertilizer, bury slow-release fertilizer or fermented oil cake in the soil.
There are no particular pests or diseases.
[Notes]
The Japanese name comes from the leaves being arranged in the shape of the character 田 (ta, "rice field").
