Tên Khoa học: Juncaceae
Tên tiếng Anh:
Tên tiếng Việt: Bấc (Hến)
Tên khác:

Juncaceae Juss. 1789

Cỏ nhiều năm, có thân mọc bò

Hoa thường lưỡng tính, bao hoa 3 hoặc 6 phiến, thường mầu xanh và giống với lá đài (ít khi có màu như cánh hoa), nhị 6 hoăc 3, bầu thượng 3-1 ô, noãn nhiều, đính thành 2 hàng trên giá noãn bên hoặc hiếm khi hoãn 1 và đính gốc.

Quả nang mở bằng van

Thế giới có 8 chi, 250 loài

Việt Nam có 1 chi, 4 loài

The Juncaceae, the rush family, is a rather small monocotyledonous  family of flowering plants. There are 8 genera and about 400 species. Members of the Juncaceae are slow-growing, rhizomatous, herbaceous plants, and they may superficially resemble grasses. They often grow on infertile soils in a wide range of moisture conditions. Some species may be found in temperate to frigid climates or on tropical mountains. A few rushes 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, 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. This family typically has reduced perianth segments called tepals. These are usually arranged in two whorls, each containing three thin, papery tepals. They are not bright or flashy in appearance, 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, all of the flower parts appear in a multiple of three.

The fruit is usually a non-fleshy, three-sectioned dehiscent capsule containing many seeds.

The dried pith of plants of this family was used to make a type of candle known as a rushlight.

The rush plant is called 'igusa' in Japanese and is used to weave the soft surface cover of tatami mats.