About 225 species of annuals and perennials of cosmopolitan distribution. The leaves are grassy to needle-like, channelled, compressed or cylindrical, in some species missing, their function taken over by the green stems. Flowers in terminal cymes, sometimes in a dense-head-like cluster, six-tepalled, usually greenish or brownish.
Comparatively few species are small enough for the rock garden; those that are will principally attract plantsman. The species listed are seldom available commercially but are not without appeal and worth seeking out. They require moist, humus-rich soil and a sunny open site. Propagation by division or seed in spring.