Soft rush

Juncus effusus, with the common names common rush or soft rush, is a perennial herbaceous flowering plant species in the family Juncaceae. It is used in various parts of the world for weaving. The pith of the stem is believed to have medicinal qualities and it is used in the treatment of sore throats, jaundice, oedema (fluid retention causing swelling) and acute urinary tract infection.

Find more about this plant on Wikipedia.