Xyris jupicai Rich.

The widest-ranging of all New World Xyrids and the most ample ecologically, Xyris jupicai is a frequent invader of disturbed or fallow open wetlands within its extensive range. In the southeastern United States it frequently shares habitat with two other species of its complex, namely X. difformis var. difformis and X. laxifolia. It differs from both in its lack of red pigmentation, from X. difformis by its more erect leaves and narrower, less prominently ribbed scapes, and from X. laxifolia by its narrower leaves and scapes, shorter, narrower, paler spikes, and translucent (rather than mealy), shorter seeds. Nonetheless, some difficult "calls" arise since all three flower at the same time and occasional chance hybrids do form.

Herbs, annual, rarely biennial, cespitose or solitary, 10--100 cm. Stems compact. Leaves erect or ascending in narrow fans, 5--60 cm; sheaths straw-colored, light green, or brown, smooth; blade green, linear, flattened, 2--5(--15) mm wide, smooth, margins smooth or papillate. Inflorescences: scape sheaths exceeded by principal leaves; scapes linear, terete, distally oval, (0.5--)1--1.5(--2) mm wide, smooth, 1--2-ribbed, ribs papillate; spikes ovoid to ellipsoid or cylindro-lanceoloid, 7--15(--25) mm, apex acute; fertile bracts 5--7 mm, margins entire, apex rounded. Flowers: lateral sepals included, slightly curved, 5--7 mm, keel scarious, lacerate, thin; petals unfolding in morning, blade obtriangular, 3 mm; staminodes bearded. Seeds translucent, ellipsoid, 0.4--0.5 mm, faintly ribbed. 2n = 18.

Ala., Ark., Del., Fla., Ga., La., Md., Miss., N.J., N.C., Okla., S.C., Tenn., Tex., Va.; Mexico; West Indies; Central America; South America.

Flowering summer--fall (all year south).

Moist sands, sandy peats of savannas, flatwoods, swales, shores, ditches, and roadsides, particularly in disturbed situations; 0--350m.

Xyris anceps Persoon 1805, not Lamarck 1791; X. arenicola Miquel; X. communis Kunth; X. gymnoptera Grisebach; X. jupicae Michaux; X. jupicai var. brachylepis Malme; X. macrocephala f. minor (Martius) M. Kuhlman & Kuhn

Xyris jupicai Rich. Act. Soc. Hist. Nat. Paris 1: 106. 1792
Xyris communis Kunth, Enum. PI. 4: 12. 1843. Xyris surinatnensis Miq. Linnaea 17: 58. 1843. Xyris arenicola Miq. Linnaea 18: 75. 1844. Xyris acuminata Miq.; Steud. Svn. Cyp. 284. 1855. Xyris gymnoptera Griseb. Cat. PI. Cub. 223. 1866.
Somewhat tufted or annual; leaves linear, 12-30 (-40) cm. long, 3-5 mm. broad, acute, smooth, or rarely minutely tuberculate beneath; sheath occupying one third to one half the length of the leaf, tawny or somewhat rusty below, somewhat dilated at the base; peduncles usually 30-50 (-65) cm. tall, 1-2 mm. broad, bicostate or unicostate, smooth, the peduncular sheath usually 8-15 cm. long, rusty or chestnut-colored and shining below; spike many-flowered, ovoid or ellipsoid, 8-13 mm. long, 5-7 (-8) mm. thick, the outer bracts ovate-elliptic, 2-3 mm. long, nearly rounded at the apex, the flowering bracts obovate, 5-6 (-7) mm. long, 3.5-4.5 mm. broad, entire, tawny or rusty and somewhat shining, with a grayish-green or green, ovate or elliptic dorsal area about 2 mm. long; lateral sepals narrowly spatulate-linear or lanceolate, 3.5-5 mm. long, about 0.6 mm. broad, acute at the apex; keel narrow and entire below, broader and lacerate-dentate or shortly lacerate-fimbriate from somewhat above the middle to the apex; seeds ellipsoid, about 0.5 mm. long. Very variable in size.
Type locality: Cayenne.
Distribution: Maryland to Florida and Texas; southward to British Honduras; Cuba, Jamaica, Haiti, and Puerto Rico; also widely distributed in South America to Uruguay.

Xyris jupicai, common name Richard's yelloweyed grass, is a New World species of flowering plants in the yellow-eyed-grass family. It is widespread in North America, South America, Mesoamerica, and the West Indies.

Xyris jupicai is a perennial herb up to 100 cm (40 inches) tall with grass-like leaves up to 60 cm (2 feet) long, and yellow flowers.

Xyris jupicai là một loài thực vật hạt kín trong họ Hoàng đầu. Loài này được Rich. miêu tả khoa học đầu tiên năm 1792.