Juncus acutus, the spiny rush, sharp rush, or sharp-pointed rush, is a flowering plant in the monocot family Juncaceae.
It grows in salt marshes and on dunes and is reliable for reducing erosion rates. In some countries like Australia, it is considered to be an invasive weed and the spines harmful to young children.
Juncus acutus is a perennial that can be to 1.5 meters (4.9 ft) tall in all kinds of soils, in areas which go from extremes in flood and dry like dunes or that just stay wet like lowland grassland and grassy woodland, riparian vegetation, freshwater wetland, and saline and subsaline wetlands.
Found principally in low-lying damp, low fertility areas like sandy seashores and dune slacks and coastal flats, occasionally in salt marshes and disturbed saline areas, mine dumps, lowland grassland, and grassy woodland, riparian vegetation, freshwater wetland, and saline and subsaline wetlands[
Pith filled stems and leaves arise from the base at different angles giving the plant a globe shape. The leaves form a basal sheath around the flower stem leaves and end with a stiff sharp point.
The flower stems are 2 millimeters (0.079 in) to 4 millimeters (0.16 in) in diameter and 4 centimeters (1.6 in) to 13 centimeters (5.1 in) long and are similar to the leaves. They emerge from the base at all angles and each have 1 - 6 flowers. Each flower has 6 stamens and 4 centimeters (1.6 in) to 25 centimeters (9.8 in) long bracts that terminate in a stiff and sharp point. The flowers are hermaphrodite and are pollinated by the wind.
Fruits are oval 3-celled brown capsules 4 millimeters (0.16 in) to 6 millimeters (0.24 in). The 1.2 millimeters (0.047 in) to 2 millimeters (0.079 in) long brown seeds have a tail at each end.
