1 Keel of the lateral sepals shortly ciliate-scabrid (or sometimes entire in X. brevifolia, and then the bract tips purplish-tinged).

  2 Plants small, usually < 30 cm tall; principal leaves usually < 10 cm long; mature spikes < 1 cm long when mature.

    3 Leaves filiform, with expanded brownish lustrous bases, usually exceeding the sheath of the scape; [plants of s. AL and the FL Panhandle]

    3 Leaves linear, the bases not expanded, shorter than, equaling, or slightly exceeding the sheath of the scape; [plants collectively more widespread].

      4 Keel of the lateral sepals straight to slightly curved, remotely ciliate or entire; spikes broadly ovoid to subglobose, the bracts loose, bicolored, the distal portions maroon or purplish and often with erose margins

      4 Keel of the lateral sepals strongly curved, densely ciliate; spikes lance-ovoid to ovoid, the bracts entire, not purple-tinged, and lacking erose borders.

        5 Plants perennial; leaves ascending, green with a distinct brown patch at the base; fruiting spikes ovoid, blunt, somewhat 2-edged from the strongly keeled outer bracts

        5 Plants annual; leaves flabellate arranged, spreading to recurved against the substrate, usually maroon; fruiting spikes often elongated and acute, not 2-edged

  2 Plants large, usually > 30 cm tall; principal leaves > 10 cm long; mature spikes > 1 cm long when mature.

          6 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; [of the Mountains, Piedmont, and Coastal Plain]

          6 Leaves spreading, not twisted or only slightly so; spikes narrowly ovoid, ellipsoidal, or oblong; bracts and sepals without a small apical tuft of hairs; bases of leaves whitish, tan, pink, purplish, maroon, or dark brown, the outermost leaves not scale-like, the plant base not appearing bulbous; [typically of the Coastal Plain, rarely disjunct inland].

             7 Seeds lustrous, translucent, broadly ovoid; spike pale brown or tan, the scales loosely imbricate; plant bases pinkish, purplish, or tan, with dark longitudinal striations on the inner leaf bases; leaves 3-20 mm wide; petal blades obovate, 6-7 mm long, opening in early morning, usually closing by mid-day

             7 Seeds farinose, dark brown (X. stricta) or pale (X. louisianica) at maturity, narrowly ellipsoid to ovoid; spike dark brown, the scales tightly imbricate; plant bases maroon, purplish, dark-brown, or reddish-brown; leaves 2-5 mm wide; petal blades triangular-cuneate, 3-5 mm long, opening at mid-day.

               8 Seeds pale when mature; plant bases maroon to maroon-brown, solitary or in small clumps; upper end of scape somewhat flattened, but not nearly as broad as the spike; spike narrowly ovoid to ellipsoid, slightly pointed

               8 Seeds dark brown when mature; plant bases dark maroon to dark brown, densely cespitose; upper end of the scape conspicuously flattened, almost as broad as the spike; spike oblong-cylindrical, obtuse

1 Keel of the lateral sepals irregularly lacerate or fimbriate, or if entire then the bract tips not purplish.

                 9 Leaves 0.5-2.0 (-2.5) mm wide, not twisted (or scarcely so); leaf bases expanded, lustrous, hard, tan to brown, neither bulbous nor deeply set in the substrate; spikes ovoid or ellipsoid, 4-15 mm long.

                   10 Bract tips smooth-edged to denticulate, not curled away from the spike, the spike thus appearing smooth; staminodia beardless

                   10 Bract tips ragged-lacerate, the tips curling away from the head, giving it a ragged appearance; staminodia bearded.

                     11 Leaves linear, flattened in cross-section, 1.0-2.0 (-2.5) mm wide, with a pale, hardened margin; scape usually narrower than the leaf blades; [e. SC south to s. FL, west to s. MS]

                     11 Leaves filiform, terete or elliptic in cross-section, 0.5-1.0 mm wide, without a paler, hardened margin; scape as broad as or broader than the leaf blades, usually less than twice the length of the longest leaves; [FL, perhaps elsewhere]

                 9 Leaves (1.5-) 2.0-25 mm wide, strongly twisted to straight, the leaf bases either not expanded, lustrous, hard, and tan to brown, or, if so, then the base also either bulbous and/or deeply seated in the substrate; spikes narrowly lanceolate, ellipsoid, to broadly ovoid, 4-40 mm long.

                       12 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).

                          13 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]

                          13 Leaves not twisted or slightly twisted, 3-25 mm wide; leaf bases either soft, not swollen, not bulbous, and pale green (X. fimbriata) or somewhat hardened and bulbous, deep red (X. panacea); scape ridges strongly scabrous or smooth; petal blades yellow; [of aquatic to very wet peaty, mucky, or sandy ponds, marshes, or other wetlands].

                            14 Leaves 5-25 mm wide; scape ridges well-developed, strongly scabrous; flowers open 1:00-3:00 p.m. EDT; [widespread]

                            14 Leaves 3-5 (-8) mm wide; scape ridges poorly-developed, smooth; flowers open 11:30-4:00 p.m. EDT; [endemic to Wakulla County, FL]

                       12 Keel of the lateral sepals lacerate, or if very shortly fimbriate, then not conspicuously exserted from the subtending bract.

                              15 Lateral sepals longer than and exserted from the subtending bracts (or if nearly hidden, the plants strongly rhizomatous).

                                16 Spikes 4-8 mm long; leaves 4-15 cm long; [in our area, ne. PA and n. NJ, and northwards]

                                16 Spikes 10-32 mm long; leaves 6-50 (-60) cm long; [in our areas, s. NJ, and southwards, and also in coastal and nearly coastal New England].

                                  17 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; [more widespread in our area]

                                  17 Leaf blades 1-2 (-3) mm wide, 6-30 cm long; spikes 10-16 mm OR 20-32 mm long; seeds 0.4-0.6 mm long; [of FL and s. AL].

                                    18 Plants perennial, mat-forming by long, scaly rhizomes; spikes 20-32 mm long; petal blades deeply lacerate at tip, the lobes 1.0-1.5 mm long; seeds with obscure alveolae; [endemic to peninsular FL]

                                    18 Plants annual, cespitose; spikes 10-16 mm long; petal blades slightly erose or serrate at tip; seeds with regular, rectangular alveolae; [endemic to Panhandle FL and s. AL]

                              15 Lateral sepals shorter than the subtending bracts, and therefore hidden (except when the spikes open to shed seeds) AND plants never rhizomatous.

                                       19 Scapes flexuous, usually spirally twisted; upper portion of leaf blades conspicuously twisted; plant bases pinkish, purplish, or dark brown, bulbous or deeply set in the substrate.

                                         20 Seeds opaque; seed surfaces slightly to densely farinose; scape 1.5-8 (-8.5) dm tall; [calcareous habitats of FL, AL, and TN].

                                           21 Plant forming a rather dense tuft; spike diverging from the scape at a 10-20° angle; [of ne. FL southward]

                                           21 Plant solitary or in small tufts; spike vertical.

                                             22 Scape 3-7 dm tall; leaf sheaths and blade surfaces mostly smooth or slightly rough-papillose only along the keels and edges; scapes with 5-7 sharply angled ridges, densely papillose on the ridges and in the grooves; stem base with or without short-ascending rhizomes

                                             22 Scape 1.5-4 dm tall; leaf sheaths and blade surfaces rough-papillose on the surfaces and along the keels and edges; scapes with 2 ridges, somewhat flattened and winglike upwards, slightly papillose on the ridges only (the grooves smooth); stem base lacking rhizomes

                                         20 Seeds translucent; seed surfaces not farinose; scape 2-11 dm tall, but usually > 5 dm tall; [collectively widespread in acidic habitats of the Coastal Plain (and rarely Piedmont), NJ south to s. FL, west to e. TX)].

                                               23 Base of plant deeply set in the substrate, without distinct outer scale leaves; leaf bases not noticeably expanded, the plant base therefore not bulbous; leaves smooth, 2-4 mm wide; petal blades ca. 3 mm long

                                               23 Base of plant shallowly set on the substrate, often with short, black outer scale leaves; leaf bases noticeably expanded, the plant base therefore appearing bulbous; leaves either smooth and 5-10 mm wide, or scabrous and 2-10 mm wide; petal blades ca. 5 mm long.

                                                 24 Leaf and scape surfaces smooth (or scabrous only along margins and ridges); petal blades obovate, white or yellow; seeds ovoid or ellipsoid, 0.5-0.6 mm long

                                                 24 Leaf and scape surfaces prominently papillose or tuberculate-scabrid; petal blades suborbicular, yellow; seeds narrowly ovoid or narrowly ellipsoidal, ca. 1.0 mm long

                                       19 Scapes usually not flexuous, usually not spirally twisted; upper portion of leaf blades not conspicuously twisted; plant bases variously colored, flabellate or equitant and set at ground level.

                                                    25 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.

                                                      26 Fruiting spikes mostly 5.5-7.5 mm long; spikes subtended by 2 linear-lanceolate, leaf-like bracts, green with scarious margins; [known only from Long Island, NY]

                                                      26 Fruiting spikes mostly 8-25 mm long; spikes not subtended by leaf-like bracts; [collectively widespread].

                                                        27 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; petals yellow

                                                        27 The 2 principal scape ridges not abruptly flattened and winglike below the spike, their combined width < the scape proper, which is itself flattened (narrowly elliptic in cross-section); fruiting spikes mostly (10-) 20-25 mm long; seeds 0.8-1.0 mm long, dark when ripe, fusiform to narrowly elliptic, 2-3× as long as wide, with lines of very fine papillae, these however obscured by a farinose covering; petals yellow or white

                                                    25 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.

                                                          28 Seeds farinose, very dark; surfaces of leaves tuberculate-scabrid, the leaves strongly ascending, linear, generally > 10 cm long; leaves generally dull-colored.

                                                            29 Mature spikes ovoid to ellipsoid, acute to obtuse; plants typically in large dense tufts; leaves 20-50 cm long, 3-12 mm wide, the older ones with dark-brown to gray bases, the younger with tan bases

                                                          28 Seeds translucent, not farinose; surfaces of leaves smooth (or sparsely tuberculate-scabrid in X. curtissii, which also has leaves linear-curvate and generally < 10 cm long); leaves generally a bright yellowish-green above the base.

                                                              30 Leaves spreading-recurved to erect, 3-13 cm long, 1-4.5 mm wide; scapes at mid-length 0.4-0.6 (-0.7) mm wide; mature spikes 3-7 (-12) mm long; fertile bracts 3-5 mm long; leaf bases various; old flowers fugacious, not persisting on spikes; seeds 0.3-0.5 mm long.

                                                              30 Leaves ascending to erect, 5-60 cm long, 2-5 (-15) mm wide; scapes at mid-length (0.5-) 1.0-1.5 (-2.0) mm wide; mature spikes 7-15 (-25) mm long; fertile bracts 5-7 mm long; leaf bases tan to brown; old flowers often persisting on spikes, drying blackish; seeds 0.4-0.5 mm long