The Juncaceae, or the Rush Family, is a rather small monocot flowering plant family. There are 8 genera and about 400 species. Many of these slow-growing plants superficially resemble grasses, though are herbs or woody shrubs, growing on infertile soils. Some may be found in temperate to frigid climates or on tropical mountains. They grow on wet or damp soils, others on dry soils. A few are annuals, but most are perennials.
The leaves are evergreen and well-developed in a basal aggregation on an erect stem. They are alternate and tristichous (i.e. with 3 rows of leaves up the stem, with each row of leaves arising one-third of the way around the stem from the previous leaf). Only in the genus Distichia are the leaves distichous. The rushes of the genus Juncus have flat, hairless leaves or cylindrical leaves. The leaves of the wood-rushes of the genus Luzula are always flat and bear long white hairs.
The plants are hermaphroditic or, rarely, dioecious. The small and insignificant flowers are arranged in inflorescences of loose cymes, but also in rather dense heads or corymbs at the top of the stem or at its side. Typical for this family are the tepals (or perianth segments). There is no clear distinction between petals and sepals. They are usually arranged with two whorls, each containing three thin, papery tepals. They are not brightly colored and their color can vary from greenish to whitish, brown, purple, black, or hyaline. There are three stigmas in the center of the flowers. As is characteristic of monocots, everything is a multiple of three.
The rush plant is called 'igusa' in Japanese and is used to weave the soft surface cover of tatami mats.