Cyperus distans aka Piedmont Flatsedge

Cyperus distans is a sedge in the Cyperaceae family. It is perennial, so it lives for more than two years. Its names include slender cyperus and Piedmont flatsedge. It is native to southeastern North America, Mexico, and South America. It also grows through much of the tropics and subtropics. People gather wild plants for food, medicine, and other useful goods. Useful Tropical Plants gives its 2018 IUCN status as Least Concern. It notes a wide range and no known major threats.

This grass-like plant grows alone or in small clumps. Its stems, called culms, rise from a short, corm-like rhizome. A rhizome is a stem that grows below ground. Both sources give a height of about 1.6 feet [0.5 metres]. The fuller plant account gives 1.1–3.6 feet [0.35–1.1 metres]. That range is wider than the listed garden height. PFAF lists flowers and ripe seeds from August to September. Each flower has both male and female organs. The accounts say little about leaf shape or flower colour.

In the wild, this sedge grows in marshes and wet grasslands. It also grows by rivers, roads, and trails. It grows in forests, swamps, and on slopes with drier soil. Chinese records range from near sea level to 5,900 feet [1,800 metres]. For garden use, PFAF lists moist or wet soil without shade. It accepts sand and loam, from slightly acid to slightly alkaline soil. Useful Tropical Plants says it prefers moist sandy loam. PFAF suggests bog gardens and garden beds. Its ability to survive British winters outdoors is not clear. PFAF doubts it will thrive outside the mildest areas.

PFAF says to sow seeds on the compost surface in spring. Keep the compost moist while the seeds sprout. They may sprout in two to six weeks at 18°C. PFAF says to keep young plants under glass through their first winter. Plant them out after the last expected spring frost. You can also split plants in spring or autumn. Lifted tubers need cool storage free of frost from autumn until spring. Useful Tropical Plants says the plant is invasive in Fiji. This local warning conflicts with PFAF's view that it is not a weed.

Records list food uses for both raw and cooked tubers. People also add them to sauces. In folk medicine, people use root juice to treat fever. This use does not prove that the treatment works. People use the leaves to make hats and mats. Both sources list no known hazards. That does not prove safety for every person or pet.