Cyperus surinamensis Rottb.

Brazil: In the southern part of Brazil, flowering occurs during the summer months.
China: Cyperus surinamensis flowers and fruits from March to September.
Nicaragua: C. surinamensis flowers and fruits all year round.
West Indies: Cyperus surinamensis flowers and fruits several times a year, intermittently.

Cyperus surinamensis behaves as an annual or vivacious species depending on temperature and humidity conditions during the year. It multiplies vegetatively by rhizome and also produces seeds.

Cyperus surinamensis grows in shady or sunny sites, muddy or sandy shallows in fresh or brackish water.

Brazil: C. surinamensis is a very common species along the Brazilian coast. It accepts poor and slightly salty soils. It grows best in rich, moist soils. It likes high temperatures and sunny areas.
China: C. surinamensis is an exotic species that grows along pond shores and roadsides in humid situations, from 0 to 200 m above sea level.
French Guiana: Cyperus surinamensis is a native species that grows in wet grasslands.
Nicaragua: Cyperus surinamensis is a frequent native species on very wet disturbed soils, in all parts of the country, from 0 to 700 m altitude.
West Indies: Cyperus surinamensis is a native species that grows in wet meadows or well-watered areas, from 0 to 100 m altitude.

Local harmfulness

Brazil: Cyperus surinamensis is a weed that infests ruderal areas, abandoned places, lawns. It can even develop between stones of little used roads.
French Guiana: Cyperus surinamensis is a fairly common weed of wet pastures, present in 12% of grassland plots. It is very rarely abundant, reaching locally 15% cover.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Cyperus%2520surinamensis