Paspalum distichum is a species of grass. Common names include knotgrass, water finger-grass, couch paspalum, eternity grass, gingergrass, and Thompson grass.
Its native range is obscure because it has long been present on most continents, and in most areas it is certainly an introduced species. Its native range probably includes parts of the tropical Americas.
How to get rid of:
Weeds can be removed manually by uprooting or cutting them close to the ground from time to time.