Perennials, tall, rigid. Leaves basal, terete, non-septate, pungent; leaf tip sclerenchymatous, sharp-pointed; medulla of rounded cells; vascular bundles scattered over most of T.S.; auricles absent. Stomata in longitudinal furrows. Lower bract apparently forming a prolongation of stem. Inflorescence terminal. Flowers in heads; floral bracteoles absent; peduncles ±incrassated. Stamens 6, rarely 3. Seeds with distinct outer seed-coat forming two appendages or rarely appendages inconspicuous.