Xyris difformis var. curtissii
Sida 2: 255. 1966.
Herbs, 15–20 cm. Leaves spreading-ascending in broad fans, mostly under 10 cm; sheaths reddish or purplish, rugulose-papillate; blade dull green, linear–sword-shaped, 1–4 mm wide, often papillate, margins somewhat scabrous. Inflorescences: scape sheath base rich rich, deep red-brown, lustrous; scapes linear-filiform, angulately terete, not much widened distally, several-ribbed, ribs equally prominent, somewhat scabrous; spikes mostly 5 mm or less. Seeds translucent. 2n = 18.
Phenology: Flowering summer–fall.
Habitat: Moist to wet sands or sandy peats of bog slicks, sphagnous areas, pine savanna, pond shores, and acid seeps
Elevation: 0–200 m
Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tex., Va., Central America (Belize).
Xyris difformis var. curtissii remains distinct even when mixed with the other two varieties, a common event in the southern Atlantic and Gulf coastal plains.