Nymphoides indica aka Robust Marshwort

Nymphoides indica, or water snowflake, is a tender aquatic perennial. It belongs to the Menyanthaceae family. Its native range runs from tropical and subtropical Asia to the southwestern Pacific. It grows in wet tropical climates and roots in mud. In Fiji, it grows in ponds and other wet places. It also grows wild beyond its native range, including southern Florida.

This plant has a thick rhizome and floating leaves. Garden plants reach about 0.5 feet (0.15 metres) high. Their spread reaches about 2 feet (0.61 metres). Underwater stems can reach 4.9 feet (1.5 metres) long. This stem length differs from the height above water. The flat, round leaves are bright green and resemble water-lily leaves. They measure about 0.17–0.67 feet (0.05–0.20 metres) across. Useful Tropical Plants describes the foliage as evergreen. New plantlets form at the leaves and help the plant spread.

White flowers rise on stalks above the floating leaves. Several flowers form a cluster called an umbel. Each flower has a yellow centre and five lobes. Fine hairs and fringed edges give the flowers their snowflake look. Flowers reach about 0.08 feet (0.025 metres) across. Missouri Botanical Garden lists flowering from July to August. Each bloom lasts just a day. The flowers provide a clear contrast with the green leaves. Sources also record fruit as a cooked food.

Grow water snowflake in full sun or part shade. It prefers rich, sandy loam beneath the water. Keep the roots under 1–2 feet (0.30–0.61 metres) of water. Plants can root in a pond bottom or submerged containers. It survives outdoor winters in USDA zones 8–11. In colder places, gardeners can grow it as an annual. Containers can move indoors before autumn frost. A greenhouse or an aquarium with a grow light provides winter shelter. Seeds offer one means of propagation. Separating the leaf-borne plantlets is the easier method.

Water snowflake suits water gardens, pools, and small ponds. Warm winters can allow vigorous spread, so it has weed potential. Missouri Botanical Garden reports no major insect or disease concerns. People harvest it from the wild for local food use. They cook young leaves, stems, flower buds, and fruit. These parts may be boiled or added to curries. Useful Tropical Plants reports no known hazards. That report does not establish safety for pets. It also records a traditional wound plaster made from stems, leaves, and flowers.