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FOC | Family List | FOC Vol. 24 | Xyridaceae

1. Xyris Linnaeus, Sp. Pl. 1: 42. 1753; Gen. Pl. ed. 5; 25, 1754.

黄眼草属 huang yan cao shu

Herbs perennial or rarely annual. Leaves equitant; leaf sheath sometimes with a short ligule; leaf blade linear to ensiform, smooth, papillose, rugose, or scaberulose. Peduncle scapelike, terete to compressed, sometimes winged or ribbed. Spikes few to many flowered; bracts brownish yellow to blackish brown, dull or shining, conchiform, rigid, abaxially minutely papillose toward apex when young, midvein conspicuous, margin scarious, entire, ciliate, fimbriate, or lacerate, apex emarginate, rounded, or acute. Sepals 3; lateral sepals with keel entire, dentate, or ciliate, wings membranous; median (anterior) sepal enclosing corolla or sometimes ± reduced or obsolete, thin and membranous, 1--3(--5)-veined. Petals 3, free; limb obovate; claw long and narrow. Stamens usually 3; filaments flattened; anthers basifixed, extrorse, dehiscing by vertical slits. Staminodes 3 or rarely absent, alternate with petals, often clawed, 2-cleft or 2-brachiate and branches with penicillate hairs. Ovary usually sessile, 1- or 3-loculed or imperfectly 3-loculed. Style filiform, apex 3-branched; stigmas usually U-shaped. Seeds obovoid to ellipsoid, longitudinally striate, apex usually apiculate.

About 280 species: mainly in tropical and subtropical America, some species in Africa, Asia, and Australia; six species (one endemic) in China.

1 Leaf blade usually 4--6 mm wide, with numerous, prominent, transverse ribs connecting longitudinal veins   1 Xyris indica
+ Leaf blade 1.5--3.5 mm wide (rarely to 5 mm in X. capensis), without transverse ribs.   (2)
2 (1) Young bracts not papillose abaxially   2 Xyris capensis var. schoenoides
+ Young bracts papillose abaxially.   (3)
3 (2) Leaf blade rigid, margin thickened   3 Xyris complanata
+ Leaf blade soft, margin not thickened.   (4)
4 (3) Median bracts orbicular and sparsely lacerate-fimbriate at apex; leaf blade acute at apex   4 Xyris bancana
+ Median bracts spinulose and with a papillose triangle at apex; leaf blade emarginate to obtuse or acuminate at apex.   (5)
5 (4) Median sepal ca. 3.5 mm; stamens 0.9--1.3 mm; inner anther locule shorter than outer one; staminodes shorter than stamens   5 Xyris pauciflora
+ Median sepal ca. 2.5 mm; stamens ca. 0.4 mm; inner anther locule longer than outer one; staminodes longer than stamens   6 Xyris formosana

Lower Taxa


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