1	"Calyx lobes 4"	2
1	"Calyx lobes 2"	4
2	"Corolla pale pink with darker pink spots on the palate"	"Utricularia westonii"
2	"Corolla bright pink (or sometimes white), with yellow spots on the palate"	3
3	"Spur of corolla about as long as the lower lip"	"Utricularia tenella"
3	"Spur of corolla much shorter than the lower lip"	"Utricularia multifida"
4	"Corolla yellow, apricot or orange-yellow"	5
4	"Corolla white or shades of red, violet or brown, usually with a yellow palate"	16
5	"Corolla spotted with dark red"	"Utricularia fulva"
5	"Corolla not spotted but may have red or brown nerves"	6
6	"Lower lip of corolla 3- or 4-lobed"	7
6	"Lower lip of corolla entire or shallowly 2-lobed"	8
7	"Lower lip of corolla 3-lobed; bracts basisolute, bracteoles absent"	"Utricularia subulata"
7	"Lower lip of corolla 4-lobed; bracts basifixed, bracteoles present"	"Utricularia chrysantha"
8	"Bracteoles present, much narrower than the bract; terrestrial plants with simple leaves"	9
8	"Bracteoles absent; aquatic plants with divided leaves"	12
9	"Peduncle twining"	10
9	"Peduncle erect"	11
10	"Corolla ±5 mm long"	"Utricularia circumvoluta"
10	"Corolla 10–15 mm long"	"Utricularia involvens"
11	"Corolla 6–10 mm long; inflorescence 3–20 cm high"	"Utricularia bifida"
11	"Corolla 10–15 mm long; inflorescence 25–55 cm high"	"Utricularia odorata"
12	"Inflorescence with a whorl of ellipsoid floats above the middle"	13
12	"Inflorescence without a whorl of floats or with narrowly fusiform floats at or near the base"	14
13	"Floats shortly stipitate; seeds lenticular with a narrow wing"	"Utricularia muelleri"
13	"Floats sessile; seeds prismatic and winged on all the angles"	"Utricularia stellaris"
14	"Ultimate segments on each leaf few (2–8)"	"Utricularia gibba"
14	"Ultimate segments on each leaf very numerous (20–80)"	15
15	"Primary segments 2; 1 or more scales present on the peduncle"	"Utricularia australis"
15	"Primary segments 3 or more; scales always absent"	"Utricularia aurea"
16	"Scales present on peduncle"	17
16	"Scales absent from peduncle"	25
17	"Bracts basifixed; bracteoles present"	18
17	"Bracts basisolute; bracteoles present or absent"	22
18	"Peduncle twining"	"Utricularia foveolata"
18	"Peduncle erect, not twining"	19
19	"Bracts much wider than bracteoles"	"Utricularia uliginosa"
19	"Bracts not, or not much, wider than bracteoles"	20
20	"Corolla lower lip 3-lobed"	"Utricularia minutissima"
20	"Corolla lower lip entire or emarginate"	21
21	"Inflorescence up to 5 cm tall, 1-flowered; corolla upper lip wider than calyx"	"Utricularia simplex"
21	"Inflorescence 8–30 cm tall, 3–10-flowered; corolla upper lip narrower than calyx"	"Utricularia lateriflora"
22	"Bracteoles present"	"Utricularia caerulea"
22	"Bracteoles absent"	23
23	"Spur of corolla 7–15 mm long, 0.5–1 mm thick; leaf segments flattened"	"Utricularia leptoplectra"
23	"Spur of corolla 3–5 mm long, 1–2 mm thick; leaf segments terete"	24
24	"Corolla deep violet, 7–10 mm long; leaf segments opposite"	"Utricularia biloba"
24	"Corolla white, tinged with pale violet, 4.5–6 mm long; leaf segments alternate"	"Utricularia limosa"
25	"Peduncle twining"	26
25	"Peduncle erect or ascending, not twining"	27
26	"Corolla lower lip entire, 20–40 mm wide"	"Utricularia volubilis"
26	"Corolla lower lip 3-lobed, ±6 mm wide"	"Utricularia helix"
27	"Corolla with 2 capillary lobes extending vertically above the flower"	28
27	"Corolla without capillary lobes extending above the flower"	31
28	"Capillary lobes arising from the apex of the corolla upper lip"	29
28	"Capillary lobes arising laterally from the base of the corolla lower lip"	30
29	"Corolla lower lip 5-lobed"	"Utricularia capilliflora"
29	"Corolla lower lip 3-lobed"	"Utricularia dunlopii"
30	"Corolla lower lip (excluding capillary lobes) about half as long as the spur; spur apex bifid"	"Utricularia dunstaniae"
30	"Corolla lower lip (excluding capillary lobes) greatly reduced to 3 minute deltoid teeth; spur apex rounded"	"Utricularia antennifera"
31	"Corolla lower lip 5-lobed"	32
31	"Corolla lower lip 2–4-lobed or entire"	35
32	"Corolla white"	33
32	"Corolla pink or mauve"	34
33	"Corolla ±2 mm wide"	"Utricularia quinquedentata"
33	"Corolla 4–8 mm wide"	"Utricularia holtzei"
34	"Corolla upper lip longer than the upper calyx lobe; base of lower lip with 4 rounded ridges"	"Utricularia rhododactylos"
34	"Corolla upper lip shorter than the upper calyx lobe; base of lower lip without ridges"	"Utricularia cheiranthos"
35	"Freely suspended aquatic with verticillate, narrowly linear leaves"	"Utricularia tubulata"
35	"Terrestrial or affixed aquatic; leaves not verticillate"	36
36	"Corolla bright red; spur 2–4 times as long as corolla lower lip, 2–3 mm thick"	"Utricularia menziesii"
36	"Corolla violet, mauve or white; spur shorter than corolla lower lip, or if longer then less than 2 mm thick"	37
37	"Bracts and bracteoles basisolute, the inferior parts connate to form a sleeve-like tube below the point of attachment"	38
37	"Bracts and bracteoles basisolute or basifixed, if basisolute then inferior part not connate to form a tube"	39
38	"Corolla lower lip shallowly 3-lobed or entire, with a prominent, lobed basal swelling"	"Utricularia kimberleyensis"
38	"Corolla lower lip deeply 3-lobed without a prominent basal swelling"	"Utricularia georgei"
39	"Peduncle hairy, at least near the base"	40
39	"Peduncle glabrous throughout or at the most minutely papillose at the base"	43
40	"Bracts and bracteoles ciliate"	"Utricularia lasiocaulis"
40	"Bracts and bracteoles not ciliate"	41
41	"Corolla lower lip deeply divided into 3 long linear lobes; trap appendages ciliate with fine hairs"	"Utricularia kamienskii"
41	"Corolla lower lip divided into 3 short rounded lobes; trap appendages not ciliate"	42
42	"Traps uniform, with the mouth basal and all appendages deeply laciniate"	"Utricularia kenneallyi"
42	"Traps dimorphic, with the mouth lateral and only the ventral wings laciniate"	"Utricularia leptorhyncha"
43	"Corolla white and yellow, about 3 mm long"	"Utricularia albiflora"
43	"Corolla various shades of violet, more than 4 mm long"	44
44	"Stolons absent, all leaves and traps arising from a short stem at the base of the peduncle"	45
44	"Stolons present, with leaves and traps at their nodes"	47
45	"Corolla 4–9 mm long; spur about twice as long as lower lip"	"Utricularia violacea"
45	"Corolla 10–20 mm long; spur shorter than to scarcely longer than the lower lip"	46
46	"Corolla upper and lower lips violet; lower lip with rounded entire apex and 5 or more diverging yellow ridges at the base"	"Utricularia inaequalis"
46	"Corolla upper lip cream or yellow, lower lip violet; lower lip distinctly 3-lobed, with 4 parallel yellow ridges at the base"	"Utricularia benthamii"
47	"Traps with all appendages narrowly deltoid to narrowly ovate, with margins entire; inner margins of all ciliate with numerous fine deflexed hairs"	"Utricularia lasiocaulis"
47	"Traps not as above"	48
48	"Corolla lower lip distinctly 3-lobed"	49
48	"Corolla lower lip entire or obscurely 2–4 crenate"	50
49	"Corolla lower lip lobes about as long as wide"	"Utricularia arnhemica"
49	"Corolla lower lip lobes 3 or more times as long as wide"	"Utricularia tridactyla"
50	"Leaf apex acuminate"	51
50	"Leaf apex acute to rounded"	53
51	"Traps with dorsal appendage subulate; lateral and ventral appendages apically fimbriate"	"Utricularia beaugleholei"
51	"Traps with dorsal and lateral appendages subulate; ventral appendages absent, or if present, then with margin entire"	52
52	"Corolla 15–20 mm long; lower lip transversely elliptic, entire; upper lip apex truncate or emarginate"	"Utricularia terrae-reginae"
52	"Corolla 6–12 mm long; lower lip square, obscurely 3–4 crenate; upper lip apex deeply 2-lobed"	"Utricularia hamiltonii"
53	"Spur of corolla subulate with apex acute"	"Utricularia triflora"
53	"Spur of corolla cylindrical or conical with apex obtuse"	54
54	"Peduncle hollow; none of the trap appendages with fimbriate margins; lower lip of the corolla without conspicuous ridges at the base"	55
54	"Peduncle not hollow; at least some of the trap appendages with fimbriate margins; lower lip of corolla with conspicuous ridges at the base, with the central ridges yellow"	56
55	"Corolla with lower lip at least twice as long as spur"	"Utricularia singeriana"
55	"Corolla with lower lip shorter than spur"	"Utricularia fistulosa"
56	"Central yellow pair of ridges not projecting distally beyond the ridges on either side"	"Utricularia uniflora"
56	"Central yellow pair of ridges projecting distally beyond the ridges on either side"	57
57	"Inflorescence 1–5 cm tall, usually 1-flowered; corolla 6–10 mm long"	"Utricularia monanthos"
57	"Inflorescence 10–50 cm tall, 1–many-flowered; corolla 12–22 mm long"	"Utricularia dichotoma"