1	"Placentation parietal; ovary unilocular; capsule walls papery, not thickened towards the apex; seeds ovoid to elliptic, 0.3-0.6 mm long (worldwide tropics and subtropics; in Australia concentrated in the tropics except for two species that extend into moist temperate regions of the eastern mainland States) (Section Xyris)"	2
1	"Placentation axile; ovary trilocular or incompletely so; capsule walls not papery, mostly thickened towards the apex; seeds oblong to fusiform, 0.9-1.5 mm long (confined to the temperate regions of south-western and south-eastern Australia) (Section Pomatoxyris)"	8
2	"Leaf surface smooth, leaves flat"	3
2	"Leaf surface papillate or scabrid, at least basally, leaves flat or subterete"	5
3	"Leaves with many distinct longitudinal and transverse veins; lamina (1.2-)5-13 mm wide, margin smooth"	"Xyris indica"
3	"Leaves with indistinct veins (excluding marginal vein which is often prominent), transverse veins not visible; lamina 0.24(-5) mm wide, margin denticulate or papillate, rarely smooth"	4
4	"Robust herbs with many scapes (sometimes depauperate); leaves (60-)loo-300(-570) mm long; leaf margin thickened and densely papillate, rarely smooth; inflorescence (excluding scape) usually 5-30 mm long, (4-)lo-50-flowered; fertile bracts with emarginate apex; staminodes present"	"Xyris complanata"
4	"Slender herbs with few scapes; leaves (6-)20-60(-80) mrn long; leaf margin denticulate, not thickened; inflorescence (excluding scape) 1.5-4.5 mm long, 1-7-flowered; fertile bracts with apex rounded, never emarginate although rarely split; staminodes absent"	"Xyris oligantha"
5	"Dorsal stomate field of fertile bract covering one-quarter to one-third of the total length of the bract and less than one-fifth of the total width, distinctly defined from surrounding epidermis"	6
5	"Dorsal stomate field of fertile bract covering one-third to one-half the total length of the bract and one-quarter to one-third of the total width, grading into surrounding epidermis"	7
6	"Leaves flat, 13-40(-50) mm long, 1.5-3 mm wide, ligule usually present although sometimes small; bract margin distally sparsely fimbriate; seeds with 16-21 longitudinal ridges, and 15-26 transverse ridges"	"Xyris pusilla"
6	"Leaves subterete, 25-160 mm long, 0.8-1.8 mm wide, ligule absent; bract margin distally entire; seeds with 12-14 longitudinal ridges, and 2 or 3 transverse ridges"	"Xyris pauciflora"
7	"Sterile bracts 4, basal pair of sterile bracts usually as long as other sterile bracts; fertile bracts with apex entire to + lacerate; stomate field often keeled"	"Xyris juncea"
7	"Sterile bracts (6-)8, basal pair of sterile bracts shorter than other sterile bracts; fertile bracts with apex densely fimbriate; stomate field never keeled"	"Xyris cheumatophila"
8	"Staminodes present"	9
8	"Staminodes absent"	18
9	"Anther locules confluent; staminodes T-shaped, inconspicuous, glabrous"	"Xyris gracillima"
9	"Anther locules free; staminodes Y-shaped, conspicuous, with moniliform hairs"	10
10	"Leaves flat, with margin thickened, differentiated, and more or less papillate"	11
10	"Leaves subterete, with margin not thickened, undifferentiated, and smooth"	14
11	"Inflorescence with basal pair of sterile bracts shorter than the next more distal pair"	"Xyris gracilis"
11	"Inflorescence with basal pair of sterile bracts equal to or longer than the next more distal pair"	12
12	"Inflorescence with basal pair of sterile bracts attenuate; petal limbs not bilobed; anthers trapezoid, 0.9–1.2 mm long; style branches 1.1–1.7 mm long"	"Xyris muelleri"
12	"Inflorescence with basal pair of sterile bracts rounded or rarely shortly acute; petal limbs bilobed; anthers oblong to trapezoid, 1.5–2.6 mm long; style branches 2.5–5 mm long"	13
13	"Leaf 0.6–1.5 mm wide; inflorescence 3- or 4-flowered; lateral sepal lamina (0.7–)0.9–1.3 mm wide"	"Xyris tasmanica"
13	"Leaf 1.4–2.4 mm wide; inflorescence c. 10-flowered; lateral sepal lamina 0.4–0.7 mm wide"	"Xyris bracteata"
14	"Sterile bracts usually appearing in 5 longitudinal columns (occasionally not so in X. operculata); capsule with indehiscent apical cap"	15
14	"Sterile bracts appearing spirally inserted, not in 5 longitudinal columns; capsule dehiscing almost to apex (apical cap absent)"	16
15	"Bract with margin distally hirsute"	"Xyris lanata"
15	"Bract with margin distally entire or erosate to lacerate"	"Xyris operculata"
16	"Fertile bracts distally spinulose"	"Xyris laxiflora"
16	"Fertile bracts distally lacerate"	17
17	"Inflorescence c. 30-flowered; lateral sepals with lamina distally papillate"	"Xyris ustulata"
17	"Inflorescence c. 4-flowered; lateral sepals with lamina distally smooth"	"Xyris marginata"
18	"Anther locules free"	"Xyris atrovirida"
18	"Anther locules confluent"	19
19	"Inflorescence less than 7 mm long (rarely to 9 mm) and less than 6 mm wide"	20
19	"Inflorescences at least 7 mm long and at least 6 mm wide"	23
20	"Fertile bract with margin distally more or less lacerate"	"Xyris flexifolia"
20	"Fertile bract with margin distally entire"	21
21	"Style undivided; inflorescence (5–)6–12-flowered; scape 0.6–1.4 mm wide; fertile bracts 4.5–6.5 mm long"	"Xyris indivisa"
21	"Style 3-branched (branches 0.6–0.8 mm long); inflorescence 2–5-flowered; scape 0.4–0.5(–0.7) mm wide; fertile bracts 3.5–4(–4.5) mm long"	22
22	"Bicarinate sheath of lateral shoots usually rugose; ligule less than 1.5 mm long; scape usually less than 400 mm long; anther locules dehiscing equally (microsporangia equal in size)"	"Xyris exilis"
22	"Bicarinate sheath of lateral shoots smooth; ligule at least 1.5 mm long; scape usually more than 500 mm long; anther locules dehiscing unequally (abaxial microsporangia smaller than and distally overarched by the adaxial microsporangia)"	"Xyris inaequalis"
23	"Inflorescence less than 10-flowered; style branches 4–5 mm long"	"Xyris roycei"
23	"Inflorescence greater than 15-flowered; style branches absent or to 1 mm long"	24
24	"Leaves without ligule; margin of fertile bract with a few major splits or more or less lacerate distally; keel of lateral sepal gradually diminishing distally"	"Xyris maxima"
24	"Leaves with ligule 0.7–1.1 mm long, rarely reduced; margin of fertile bract lacerate distally; keel of lateral sepal abruptly terminating distally"	"Xyris lacera"