An Illustrated Flora of the Northern United States, Canada and the British Possessions/Xyridaceae
Nat Syst. Ed. 2, 388.
Yellow-Eyed Grass Family.
Perennial or annual tufted herbs with basal narrow equitant commonly 2-ranked leaves, and erect simple leafless scapes. Flowers perfect, mostly yellow, nearly or quite regular, solitary and sessile in the axils of coriaceous imbricated bracts (scales), forming terminal ovoid globose or cylindric heads. Sepals 3, the two lateral ones small, keeled, persistent, the other one larger, membranous (wanting in the South American genus Abolboda). Corolla inferior, with a narrow tube and 3 spreading lobes. Stamens 3, inserted on the corolla, usually alternating with as many plumose or bearded staminodia. Ovary sessile, 1-celled or incompletely 3-celled ; ovules numerous or few, on 3 parietal placentae, orthotropous ; style terminal (unappendaged in Xyris, in Abolboda appendaged at the base), 3-branched above; stigmas apical. Fruit an oblong 3-valved capsule. Seed-coat longitudinally striate. Embryo apical. Endosperm mealy or somewhat fleshy.
Two genera, Xyris L. and Abolboda H. & B., comprising some 60 species, mostly of tropical distribution in both the Old World and the New.