Genus of 2 types of rhizomatous, marginal water perennials, ane semi-time, tested than one deciduous, located in little water by streams and ponds throughout the N. hemisphere, particularly E. Asia. The bright white-removed foliage of the grassy vegetation type fan-shaped tufts. Its excellent advantage being a background herb among far more magnificent specimens is it will hold up against deplorable situations – it is not impacted by waterlogging, draughts, or frosty wintertime nights.