Yellow-eyed-grasses

Xyris

1 Keel of the lateral sepals shortly ciliate-scabrid. Leaves ascending, twisted, strongly grooved; spikes ovoid, the bracts and lateral sepals
  with a small tuft of short, reddish-brown hairs; bases of leaves abruptly expanded, pinkish or purplish (dark brown in age), the outermost
  leaves often scale-like, the plant base therefore appearing bulbous............................................................ Slender Yellow-eyed-grass
1 Keel of the lateral sepals irregularly lacerate or fimbriate.
  2 Keel of the lateral sepals long-fimbriate toward its apex, the fimbriate tip conspicuously exserted from the subtending bract (sometimes
    eroded and less conspicuous on older spikes).
    3 Leaves strongly twisted, 2-5 mm wide; leaf bases hardened, swollen, bulbous, dark lustrous brown; scape ridges smooth; petal blades
        white or yellow; [of moist to dry pinelands] ........................................................................................ Carolina Yellow-eyed-grass
    3 Leaves not twisted or slightly twisted, 3-25 mm wide; leaf bases soft, not swollen, not bulbous, and pale green; scape ridges strongly
        scabrous or smooth; petal blades yellow; [of aquatic to very wet peaty, mucky, or sandy ponds, marshes, or other wetlands]. Leaves
        5-25mm wide; scape ridges well-developed, strongly scabrous; flowers open 1:00-3:00 p.m. EDT ..... Fringed Yellow-eyed-grass
  2 Keel of lateral sepals lacerate, or if very shortly fimbriate, then not conspicuously exserted from the subtending bract.
    4 Lateral sepals longer than and exserted from the subtending bracts; scapes 5-15 dm tall. Leaf blades 5-15 mm wide;
      (20-) 30-50 (-60) cm long; spikes 10-20 (-25) mm long; seeds (0.6-) 0.7 (-0.8) mm long...................... Small's Yellow-eyed-grass
    4 Lateral sepals shorter than subtending bracts, and therefore hidden (except when spikes open to shed seeds); scapes 1.5-12 dm tall.
        5 Summit of the scape distinctly flattened and broad relative to the spike; scape ridges 2-3, the 2 most prominent comprising the
          flattened edge of the scape. The 2 principal scape ridges noticeably and abruptly flattened and winglike below the spike, their
          combined width (on fresh material) broader than the scape proper; fruiting spikes mostly 8-15 mm long; seeds 0.4-0.6 mm long,
          translucent, ovoid or ellipsoidal, about 1.5× as long as wide, with lines of very fine papillae, not farinose...Bog Yellow-eyed-grass
        5 Summit of the scape nearly terete or somewhat flattened, much narrower than the spike; scape ridges several (usually > 3), at least
          on the mid to lower portion of the scape. Leaves ascending to erect, 5-60cm long, 2-5 (-15)mm wide; scapes (0.5-) 1.0-1.5 (-2.0)mm
          wide; mature spikes 7-15 (-25)mm long; fertile bracts 5-7mm long; leaf bases tan to brown (very rarely pinkish); old flowers often
          persisting on spikes, drying blackish..................................................................................................Richard's Yellow-eyed-grass