Xyris is a genus of flowering plants, the yelloweyed grasses, in the yellow-eyed-grass family. The genus counts over 250 species, widespread over much of the world, with the center of distribution in the Guianas.[1] [2]
The leaves are mostly distichous, linear, flat, and thin or round with a conspicuous sheath at the base. They are arranged in a basal aggregation. The small, yellow flowers are borne on a spherical or cylindrical spike or head (inflorescence). Each flower grows from the axil of a leathery bract. The fruit is a nonfleshy, dehiscent capsule. In Xyris complanata, a single flower bud on the spike appears in the morning, and expands into a conspicuous flower during the afternoon hours.
The APG IV system, of 2016, places the genus in family Xyridaceae, into the order Poales in the clade commelinids, in the monocots.