4. Xyridaceae C. Agardh
黄眼草科 huang yan cao ke
Authors: Guofang Wu & Robert Kral
Herbs perennial or rarely annual. Roots fibrous. Leaves mostly basal, distichous or sometimes polystichous, sheathing; leaf blade ensiform, linear, or filiform. Scapes or peduncles usually numerous. Inflorescence terminal, a globose to cylindric head or dense spike; bracts conspicuous, spirally imbricate or decussate, persistent or sometimes caducous in fruit. Flowers bisexual, 3-merous. Sepals 3, sometimes median sepal reduced or absent, lateral sepals 2, chaffy-scarious, keeled. Corolla actinomorphic or rarely zygomorphic, usually ephemeral; petals 3, yellow, less often white or blue, free, base clawed or sometimes connate, or forming a long tube. Stamens usually 3, inserted opposite petals; filaments short, adnate to petals, rarely free; anthers 2-loculed, dehiscing longitudinally. Staminodes present or absent. Ovary superior. Style filiform, apex 3-branched or simple. Capsule oblong, 3-valved, loculicidal. Seeds with copious and ± mealy endosperm; embryo small.
About five genera and ca. 300 species: widespread in tropical and subtropical regions; one genus and six species (one endemic) in China.
Wu Kuo-fang. 1997. Xyridaceae. In: Wu Kuo-fang, ed., Fl. Reipubl. Popularis Sin. 13(3): 11--19.