Juncus effusus 'Spiralis' (Rasen-i)

Rasen-i is a variety of i-gusa (mat rush) that is used to make tatami mats.       

It has underground rhizomes from which rod-shaped stems grow upwards in a “spiral”, or “rasen” in Japanese, hence its Japanese common name. This plant has been cultivated for ornamental purposes such as planting or bonsai. Originally grown in wetlands, it is also cultivated overseas along the water’s edge.