1	"Leaves numerous, flat, involute, canaliculate, terete, or filiform, spread along the culms or all basal (if terete, leaves septate or spread along culms); inflorescence obviously terminal (rarely apparently lateral)."	2
1	"Leaves reduced to basal sheathing cataphylls or 1 or 2 well-developed terete basal leaves similar to culms, not septate; inflorescence apparently lateral or obviously terminal, with the lowest involucral bract well-developed and appearing superficially to be a continuation of the culm."	27
2	"Leaves not septate, solid."	3
2	"Leaves septate (if filiform, septa not very obvious), spread along culms, hollow or with very loose pith between septa."	15
3	"Flowers subtended by 2 bracteoles, solitary or loosely clustered (densely clustered in Juncus bufonius (occasionally) and in J. homalocaulis); leaves basal or both basal and cauline; auricles present or absent."	4
3	"Flowers without bracteoles, more or less densely clustered; leaves all basal (except in Juncus falcatus); auricles absent."	10
4	"Annuals; auricles absent but often with hyaline margins narrowing abruptly at top of sheath; both cauline and basal leaves present on a plant."	"Juncus bufonius"
4	"Perennials; auricles present; leaves all basal."	5
5	"Leaves flat (may be inrolled when dried)."	6
5	"Leaves canaliculate or terete or filiform."	7
6	"Anthers 0.3–0.6 mm long, shorter than or equalling filaments; tepals 3.0–4.5 mm long."	"Juncus tenuis"
6	"Anthers 1.2–2.0 mm long, longer than filaments; tepals 4.5–5.7 mm long."	"Juncus revolutus"
7	"Tepals no more than 3.0 mm long; base of plant with persistent fibrous remains of leaf sheaths; culms 0.2–0.5 mm diam."	"Juncus capillaceus"
7	"Tepals more than 3.0 mm long (rarely as short as 2.8 mm in Juncus cognatus but then no fibrous remains persisting at base of plant); culms 0.5–2 mm diam."	8
8	"Flowers in more or less stellate, dense clusters; stamens mostly 3, occasionally 4 to 6; outer tepals 5–6(–7.5) mm long, much longer than inner (by 0.5–1 mm)."	"Juncus homalocaulis"
8	"Flowers solitary, evenly spread along ultimate branches of inflorescence; stamens 6; outer tepals 2.8–4.2 mm long, equalling or exceeding inner tepals by less than 0.5 mm."	9
9	"Capsule much longer than tepals (by 1–2 mm); anthers 0.7–1.1 mm long."	"Juncus imbricatus"
9	"Capsule about as long as tepals (slightly shorter than to slightly exceeding them); anthers 0.3–0.6 mm long."	"Juncus cognatus"
10	Annuals.	"Juncus capitatus"
10	"Perennials (but often flowering in first year)."	11
11	"Tepals less than 3.5 mm long (rarely 3.5 mm long in Juncus antarcticus, and then leaves 0.2–0.5 mm wide); leaves 0.2–11 mm wide."	12
11	"Tepals longer than or equalling 3.5 mm long; leaves 1–3 mm wide."	14
12	"Plants dwarf, mat-forming, with a slender rhizome; culms 0.5–6 (rarely to 12) cm long; stamens 3 or rarely 6."	"Juncus antarcticus"
12	"Plants tufted, not mat-forming, with or without a rhizome; culms mostly 15–60 cm long (occasionally as short as 5 cm); stamens 3 or 6."	13
13	"Stamens 3; leaves 1.5–11 mm wide; tepals with more or less narrow hyaline margins; anthers 0.3–0.5 mm long, usually shorter than filaments; capsule exceeding or occasionally equalling outer tepals."	"Juncus planifolius"
13	"Stamens 6; leaves 1–2 (rarely to 2.5) mm wide; inner tepals with broad whitish margins; anthers 0.4–0.8 mm long, more or less equalling filament length; capsule shorter than or equalling outer tepals."	"Juncus caespiticius"
14	"Inflorescence of 1 or 2 (rarely 4) heads; culms, bracts and tepals more or less scaberulous; capsule longer than or equalling tepals, short-apiculate; often 1 or 2 cauline leaves present as well as basal."	"Juncus falcatus"
14	"Inflorescence diffuse, with 8–25 clusters at apex of branches; culms, bracts and tepals smooth; capsule much shorter than tepals, long-beaked; leaves all basal."	"Juncus capensis"
15	"Leaves unitubulose (i.e. with transverse septa only - determined by carefully splitting the culm) or leaves less than 1 mm diam. (and therefore not easy to determine position of septa)."	16
15	"Leaves pluritubulose."	26
16	"Seeds 1.3–1.9 mm long, tailed at both ends."	"Juncus canadensis"
16	"Seeds 0.3–0.7 mm long, not tailed."	17
17	"Stamens 3."	18
17	"Stamens 4–6."	19
18	"Slender plants with culms 6–30 cm long; leaves more or less filiform, 0.3–0.7(–1.2) mm diam., pluritubulose but septa not obvious; inflorescence 2–7 cm long."	"Juncus bulbosus"
18	"Moderately robust plants with culms 25–60 cm long; leaves 1–2.6 mm diam., clearly unitubulose; inflorescence 9–18 cm long."	"Juncus acuminatus"
19	"Dwarf plants with culms no more than 10 cm long at maturity (rarely to 14 cm in Juncus sandwithii); leaves more or less filiform, usually less than 1.0 mm diam.; with septa often not obvious."	20
19	"Plants with culms mostly 20–80 cm long (occasionally longer; if shorter, then with more or less numerous clusters and more or less numerous flowers, or inflorescence with more than 3 clusters, each with more than 4 flowers); leaves broader than filiform, 1–4 mm diam., with transverse septa usually obvious."	22
20	"Auricles 1–2 mm long; capsule obtuse, shortly apiculate; tufted."	"Juncus bulbosus"
20	"Auricles c. 0.5 mm long; capsule acuminate, long- or short-beaked; shortly rhizomatous, mat-forming."	21
21	"Outer tepals slightly exceeding to slightly shorter than inner tepals; inner tepals acute, with more or less narrow hyaline margins; stamens shorter than tepals; capsule longer than tepals by 0.7–1.5 mm."	"Juncus sandwithii"
21	"Outer tepals shorter than inner tepals by up to 0.5 mm; inner tepals obtuse to broad-acute, with broad hyaline margins; stamens longer than or equalling tepals; capsule equalling or exceeding tepals by up to 0.5 mm."	"Juncus thompsonianus"
22	"Capsule tapering evenly from base into long beak, longer than tepals by 1–2 mm."	"Juncus fockei"
22	"Capsule with short or long beak but not tapering evenly from base (body of capsule ovate, oblong or obovate in outline, contracting more or less abruptly to a beak)."	23
23	"Anthers longer than or equalling filaments; auricles 0.7–1.5 mm long."	24
23	"Anthers shorter than filaments; auricles 1.5–3.5 mm long."	25
24	"Rhizome robust, 2–5 mm diam.; outer tepals usually shorter than inner; tepals with long-acuminate apices strongly reflexed at maturity."	"Juncus acutiflorus"
24	"Rhizome absent or slender (less than 2 mm diam.); outer tepals usually longer than or equalling inner; tepals with acute to obtuse or acuminate apices erect or only slightly reflexed."	"Juncus articulatus"
25	"Capsule red-brown at least near apex, obtuse, usually shorter than tepals; tepals with usually broad whitish margins; seeds 0.3–0.4(–0.5) mm long."	"Juncus microcephalus"
25	"Capsule golden brown, acute, subequal to tepals; tepals with broad hyaline to yellowish margins; seeds 0.4–0.6 mm long."	"Juncus holoschoenus"
26	"Leaves terete or canaliculate, 0.3–1.2 mm diam.; anthers longer than or equalling filaments; capsule obtuse, apiculate."	"Juncus bulbosus"
26	"Leaves flattened, 1.3–3.2 mm wide; anthers shorter than filaments; capsule tapering more or less evenly to long-acuminate apex."	"Juncus prismatocarpus"
27	"Flowers without bracteoles; leaves and bracts pungent; 1 or 2 terete leaves similar to culms present, as well as several cataphylls."	28
27	"Flowers subtended by 2 bracteoles; leaves and bracts acute but not pungent; leaves all reduced to cataphylls on flowering plants (vegetative shoots are long, terete leaf-like)."	29
28	"Capsule much longer than tepals, golden brown to chestnut-brown; anthers 1.2–1.7 mm long; seeds tailed at both ends, 1.3–1.8 mm long; inner tepals with broad whitish margins (readily deciduous) near apex."	"Juncus acutus"
28	"Capsule slightly exceeding to slightly less than tepals, golden brown to red-brown to blackish; anthers 0.5–1.0 mm long; seeds not tailed, 0.5–0.8 mm long; inner tepals with more or less narrow hyaline margins near apex."	"Juncus kraussii"
29	"Inflorescence branches, upper culms and mid-region of tepals finely scabrous."	"Juncus radula"
29	"Plants not scabrous."	30
30	"Plants unisexual (rudimentary parts of the other sex present)."	31
30	"Plants bisexual."	32
31	"Culm striations 35–60; culms 65–125 cm long, 1.6–3.2 mm diam.; stomates sunken below surface of culm."	"Juncus psammophilus"
31	"Culm striations 100–200; culms 120–400 cm long, 4–9 mm diam.; stomates superficial."	"Juncus ingens"
32	"Pith continuous (may be dense or more loose, but without distinct lacunae) at least in middle portion of culms."	33
32	"Pith interrupted (with obvious lacunae in the pith) at least in middle portion of culms."	50
33	"Stamens usually 6 (occasionally fewer in some flowers in an inflorescence)."	34
33	"Stamens usually 3 (occasionally more in some flowers in an inflorescence)."	38
34	"Culm striations greater than 40; culms greater than or equalling 2.5 mm diam.; cataphylls more or less lax."	35
34	"Culm striations 40 or less; culms less than 2.5 mm diam.; cataphylls more or less tight."	36
35	"Capsule without red-brown flecks on adaxial surface, usually exceeding tepals (occasionally equalling them); flowers loosely clustered or solitary and spread out along the branches of the inflorescence (rarely densely clustered but if so then not in several discrete clusters)."	"Juncus pallidus"
35	"Mature capsule with red-brown flecks on adaxial surface, usually shorter than tepals (occasionally equalling them); flowers in dense, distant clusters at apex of branches."	"Juncus vaginatus"
36	"Flowers in dense distant clusters at apex of branches; culms 1.5–4.5 mm diam.; mature capsule with red-brown flecks adaxially."	"Juncus vaginatus"
36	"Flowers solitary and spread out along the branches of the inflorescence; culms 0.5–1.7 mm diam. (rarely to 2.5 mm in Juncus pauciflorus); capsule without red-brown flecks adaxially."	37
37	"Outer tepals 2.0–2.8 mm long; culms mid-green, very glossy."	"Juncus pauciflorus"
37	"Outer tepals 2.9–3.1 mm long; culms grey-green, dull."	"Juncus dolichanthus"
38	"Striations 10–20; culms 15–45 cm long, 0.6–1.2 mm diam.; inflorescence shorter than or equalling 3 cm long and flowers in 1–several dense discrete clusters."	"Juncus filicaulis"
38	"Striations 20–120; culms 50–170 cm long, 1.3–8.5 cm diam.; inflorescence longer than 3 cm long (occasionally culms and inflorescences slightly smaller in Juncus usitatus but then flowers solitary and spread along branches, and culms yellow-green to mid-green)."	39
39	"Inflorescence reddish overall (capsules red-brown to dark red-brown and tepals with red-brown sides)."	"Juncus phaeanthus"
39	"Inflorescence straw-coloured to golden brown overall (although either capsules or tepals may occasionally be red-brown)."	40
40	"Inflorescence with flowers in discrete dense clusters at apex of branches."	41
40	"Inflorescence with flowers solitary and spread along the branches or loosely clustered towards apex of branches."	44
41	"Stomates deeply sunken below culm surface in straight-sided pits."	"Juncus australis"
41	"Stomates superficial or slightly sunken below culm surface."	42
42	"Culms yellow-green to mid-green, not glaucous."	"Juncus alexandri"
42	"Culms grey-green to blue-green, often glaucous."	43
43	"Culms 55–110 cm long, 2.2–5 mm diam.; stomates slightly sunken."	"Juncus firmus"
43	"Culms 90–160 cm long, 3.5–8.5 mm diam.; stomates superficial."	"Juncus semisolidus"
44	"Culms grey-green to blue-green, often glaucous."	45
44	"Culms yellow-green to mid-green, not glaucous."	46
45	"Culms 55–110 cm long, 2.2–5 mm diam.; stomates slightly sunken."	"Juncus firmus"
45	"Culms 90–160 cm long, 3.5–8.5 mm diam.; stomates superficial."	"Juncus semisolidus"
46	"Cataphylls coppery to dark golden brown adaxially, lax or tightly enclosing culm; culms soft or more or less hard."	47
46	"Cataphylls silvery to pale golden brown adaxially, more or less tightly clasping culm; culms more or less soft."	49
47	"Cataphylls dull, tightly enclosing culm; culms soft; capsule mostly shorter than outer tepals."	"Juncus effusus"
47	"Cataphylls glossy at least near base, lax; culms more or less hard; capsule mostly exceeding outer tepals."	48
48	"Pith usually slightly interrupted near apex or base; cataphylls usually dark yellow-brown to dark red-brown abaxially, rarely black at very base."	"Juncus laeviusculus"
48	"Pith always continuous; cataphylls mostly dark red-brown but usually black at very base."	"Juncus alexandri"
49	"Cataphylls yellow to dark yellow-brown abaxially; striations 35–80."	"Juncus continuus"
49	"Cataphylls red-brown or occasionally golden brown; striations 20–40."	"Juncus usitatus"
50	"Culms no more than 2.5 mm diam. (about halfway along culm)."	51
50	"Culms more than 2.5 mm diam. (about halfway along culm)."	75
51	"Culm striations less than 25."	52
51	"Culm striations at least 25."	56
52	"Culms grey-green to blue-green, occasionally glaucous."	53
52	"Culms yellow-green to mid-green, never glaucous."	55
53	"Stomates sunken in sloping-sided pits; cataphylls golden brown to coppery adaxially, usually dark red-brown to black abaxially; striations widely spaced; inflorescence 6–15 cm long."	"Juncus sarophorus"
53	"Stomates superficial; cataphylls silvery to pale golden brown adaxially, straw-brown to dark yellow-brown abaxially; striations closely packed; inflorescence mostly 1.5–7 cm long."	54
54	"Inflorescence head-like or occasionally with 1 or 2 extra dense clusters; striations longer than or equalling 0.1 mm wide; tepals frequently red-tinged."	"Juncus filicaulis"
54	"Inflorescence with flowers spread out along the branches or clustered; striations mostly less than 0.1 mm wide; tepals occasionally red-tinged."	"Juncus subsecundus"
55	"Cataphylls red-brown to golden brown abaxially; culms more or less soft."	"Juncus usitatus"
55	"Cataphylls pale yellow to pale golden brown abaxially; culms more or less hard."	"Juncus ochrocoleus"
56	"Inflorescence reddish overall (capsules red-brown to dark red-brown and tepals with red-brown sides)."	"Juncus phaeanthus"
56	"Inflorescence straw-brown to dark golden brown overall (although either capsules or tepals may occasionally be at least partly red-brown)."	57
57	"Stomates deeply sunken below surface of culm."	58
57	"Stomates superficial."	60
58	"Stomates in sloping-sided pits; striations 20–40, widely separated; anthers 0.3–0.5 mm long."	"Juncus sarophorus"
58	"Stomates in straight-sided pits; striations 35–90, more or less closely packed; anthers 0.5–1.0 mm long."	59
59	"Cataphylls dark yellow-brown to red-brown; tepals with narrow hyaline margins."	"Juncus australis"
59	"Cataphylls yellow to dark golden brown; tepals with more or less broad hyaline margins."	"Juncus flavidus"
60	"Outer tepals longer than 2.5 mm long."	61
60	"Outer tepals less than or equalling 2.5 mm long."	63
61	"Culms hard; striations usually 15–30, rarely to 40; inflorescence usually 1–5 cm long."	"Juncus subsecundus"
61	"Culms soft; striations 25–115; inflorescence 7–19 cm long."	62
62	"Cataphylls yellow to dark yellow-brown; capsule shorter than or equalling outer tepals; lowest involucral bract often shorter than inflorescence."	"Juncus remotiflorus"
62	"Cataphylls usually pink-brown to red-brown; capsule longer than outer tepals; lowest involucral bract longer than inflorescence."	"Juncus aridicola"
63	"Inflorescence of several dense discrete clusters of flowers at the apex of branches."	64
63	"Inflorescence diffuse, with flowers evenly spread along branches or loosely clustered towards the apex of the branches."	67
64	"Culms yellow-green to mid-green, not glaucous."	"Juncus gregiflorus"
64	"Culms grey-green to blue-green, often glaucuous."	65
65	"Cataphylls straw-brown to dark yellow-brown, more or less tight; striations mostly less than 30; culms mostly less than 1.4 mm diam.; outer tepals mostly 2.5–4 mm long."	"Juncus subsecundus"
65	"Cataphylls mostly red-brown to black (rarely yellow-brown), more or less lax; striations 30–60; culms mostly 1.4–2.5 mm diam.; outer tepals 1.8–2.6 mm long."	66
66	"Culms hard; inflorescence 4–15 cm long."	"Juncus subglaucus"
66	"Culms soft; inflorescence usually 1–5 cm long."	"Juncus amabilis"
67	"Culms grey-green to blue-green, often glaucous."	68
67	"Culms yellow-green to mid-green, not glaucous."	71
68	"Tepals acute to obtuse; cataphylls adaxially coppery to golden brown."	"Juncus polyanthemus"
68	"Tepals acuminate to acute, often mucronate; cataphylls adaxially silvery to occasionally golden brown."	69
69	"Striations mostly 15–30."	"Juncus subsecundus"
69	"Striations 35–115."	70
70	"Culms hard; striations 35–55; inflorescence branches more or less straight."	"Juncus subglaucus"
70	"Culms soft; striations 40–115; inflorescence branches often strongly flexuous."	"Juncus aridicola"
71	"Cataphylls abaxially pale yellow to pale golden brown."	"Juncus ochrocoleus"
71	"Cataphylls abaxially dark yellow-brown to pink-brown, red-brown or black."	72
72	"Cataphylls tightly enclosing culms; tepals with broad hyaline margins."	73
72	"Cataphylls lax; tepals mostly with narrow hyaline margins."	74
73	"Culms less than 2.0 mm diam."	"Juncus usitatus"
73	"Culms 2.1–4 mm diam."	"Juncus mollis"
74	"Culms hard; inflorescence 3–10 cm long; anthers longer than or equalling filaments."	"Juncus laeviusculus"
74	"Culms more or less soft; inflorescence 1–5 cm long; anthers shorter than or equalling filaments."	"Juncus gregiflorus"
75	"Inflorescence reddish overall (capsules red-brown to dark red-brown and tepals with red-brown sides)."	"Juncus phaeanthus"
75	"Inflorescence straw-brown to dark golden-brown overall (although either capsules or tepals may occasionally be at least partly red-brown)."	76
76	"Stomates sunken below culm surface."	77
76	"Stomates superficial."	79
77	"Stomates in sloping-sided pits; striations 20–40, widely separated; anthers 0.3–0.7 mm long."	"Juncus sarophorus"
77	"Stomates in straight-sided pits; striations 35–90, more or less closely packed; anthers 0.5–1.0 mm long."	78
78	"Cataphylls dark yellow-brown to red-brown; tepals with narrow hyaline margins."	"Juncus australis"
78	"Cataphylls yellow to dark golden-brown; tepals with more or less broad hyaline margins."	"Juncus flavidus"
79	"Culms grey-green to blue-green, often glaucous."	80
79	"Culms yellow-green to mid-green, not glaucous."	82
80	"Culms more or less hard; cataphylls abaxially dark red-brown to black."	"Juncus semisolidus"
80	"Culms more or less soft; cataphylls abaxially pink-brown to red-brown."	81
81	"Cataphylls golden brown to coppery adaxially; seeds 0.4–0.5 mm long."	"Juncus polyanthemus"
81	"Cataphylls silvery to pale golden brown adaxially; seeds 0.3–0.4 mm long."	"Juncus aridicola"
82	"Inflorescence of discrete dense clusters of flowers at the apex of branches."	83
82	"Inflorescence diffuse, with flowers spread evenly along branches or in loose clusters towards apex of branches."	85
83	"Culms hard; lowest involucral bract mostly shorter than or equalling inflorescence."	"Juncus brevibracteus"
83	"Culms more or less soft; lowest involucral bract mostly longer than inflorescence."	84
84	"Culms 3–10 mm diam.; striations 65–160; outer tepals 2.0–3.0 mm long, with more or less broad hyaline margins."	"Juncus procerus"
84	"Culms 1–3 mm diam.; striations 30–65; outer tepals 1.6–2.2 mm long, with narrow hyaline margins."	"Juncus gregiflorus"
85	"Cataphylls abaxially pale yellow to pale golden brown."	"Juncus ochrocoleus"
85	"Cataphylls abaxially dark yellow-brown to pink-brown, dark red-brown or black."	86
86	"Culms soft."	87
86	"Culms hard."	88
87	"Flowers in loose to dense clusters; cataphylls lax."	"Juncus gregiflorus"
87	"Flowers solitary along branches of inflorescence; cataphylls tightly enclosing culms."	"Juncus mollis"
88	"Tepals with narrow hyaline margins."	89
88	"Tepals with broad hyaline margins."	90
89	"Anthers longer than or equalling filaments; capsule golden brown."	"Juncus laeviusculus"
89	"Anthers shorter than filaments; capsule dark golden brown to red-brown."	"Juncus brevibracteus"
90	"Capsule longer than or equalling outer tepals; lowest involucral bract mostly shorter than or equalling inflorescence; culms 1.7–2.9 mm diam."	"Juncus laeviusculus"
90	"Capsule shorter than or equalling outer tepals; lowest involucral bract mostly longer than inflorescence; culms 3–10 mm diam"	"Juncus procerus"