Juncus bufonius  commonly named Toad Rush  is a low-growing ( 6"- 12") semi-aquatic re-seeding annual rush. It is native to California and also found elsewhere in North America and beyond. This annual monocot is quite variable in appearance. It is sometimes described as a complex of variants labeled with one species name. It is generally a dark green or even bronze-tinged clumping grasslike rush with many thin stems wrapped with few threadlike leaves  and will grow in saline conditions which many other plants would not tolerate  dying in winter but re-seeding in exposed soils.