Tetraria are perennial herbs, with generally few nodes. The leaves are conspicuously sheathed with flat or incurved blades. The inflorescence is usually a narrow panicle, with the flowers being bisexual, the lower flowers being male, and there are generally three stamens and three stigmas. The fruit (a nutlet) is generally trigonous and often retains its style as a beak or crown.
(Accepted by Plants of the world online)
Recent molecular work has shown that Tetraria is polyphyletic and in need of revision.