1	Leaves divided into narrowly linear to capillary segments, ultimate segments (except U. limosa) bearing apical and often lateral solitary or fasciculate setulae; bracteoles absent; capsule globose or ellipsoid, not dorsiventrally compressed; seeds globose, lenticular, or prismatic		(2)
+	Leaves simple, orbicular to linear, glabrous, margin entire or rarely divided into broader lobes; bracteoles present; capsule globose, ovoid, or ellipsoid, often dorsiventrally compressed; seeds ovoid, obovoid, or ellipsoid, rarely globose		(9)
2 (1)	Scales not present on peduncle; persistent style often equaling or exceeding capsule.		25 U. aurea
+	Scales present on peduncle; persistent style much less than 1/2 as long as capsule		(3)
3 (2)	Scales and bracts basisolute; corolla lilac, violet, or white		(4)
+	Scales and bracts basifixed; corolla yellow		(5)
4 (3)	Lower corolla lip 2-lobed to ca. 1/2 its length; seeds globose, not winged; rhizoids present and capillary.		18 U. limosa
+	Lower corolla lip rounded to retuse; seeds lenticular, with a broad dentate wing; rhizoids apparently absent.		19 U. punctata
5 (3)	Turions (overwintering buds) absent; corolla with a few short stipitate glands; capsule laterally 2-valvate; seeds lenticular, with a broadly irregular wing.		20 U. gibba
+	Turions usually present; corolla without external stipitate glands; capsule circumscissile; seeds prismatic, (4 or)5- or 6-angled (unknown for U. intermedia)		(6)
6 (5)	Stolons all with green, many × divided leaves with traps, leaf segment capillary or slightly flattened		(7)
+	Stolons dimorphic, bearing either green leaves with narrowly linear segments with few or no traps or bearing colorless much reduced leaves with traps		(8)
7 (6)	Margins of lower corolla lip deflexed; palate hairy; bracts ovate.		21 U. vulgaris
+	Margins of lower corolla lip spreading; palate glabrous; bracts orbicular.		22 U. australis
8 (6)	Palate of lower corolla lip with a prominent rounded basal swelling; spur subulate, slightly shorter than lower corolla lip; rhizoids present and filiform.		23 U. intermedia
+	Palate of lower corolla lip without a prominent rounded swelling but much elongate with a raised marginal rim; spur saccate to obtusely broadly conic, ca. 1/2 as long as lower corolla lip; rhizoids absent.		24 U. minor
9 (1)	Bracts and bracteoles basisolute, attached just above to below middle		(10)
+	Bracts and bracteoles basifixed		(17)
10 (9)	Leaves linear to narrowly obovate, vein 1; scales numerous; calyx lobes ± equal in size, upper lobe shorter than upper corolla lip		(11)
+	Leaves reniform, orbicular, or obovate, veins dichotomously branched; scales absent (seldom few in U. striatula); calyx lobes very unequal in size, upper lobe much longer than upper corolla lip		(12)
11 (10)	Corolla violet, pink, or white, marked with yellow at throat, palate without hooked processes.		3 U. caerulea
+	Corolla pale bluish purple, palate with hooked processes.		4 U. warburgii
12 (10)	Plant with a basal tuber		(13)
+	Plant without a basal tuber		(14)
13 (12)	Spur of corolla ± as long as or shorter than lower corolla lip; leaf blade 1-3 cm.		12 U. brachiata
+	Spur of corolla much longer than lower corolla lip; leaf blade 0.4-0.8 cm.		13 U. forrestii
14 (12)	Trap mouth with a dorsal deeply 2-cleft appendage; corolla spur subulate, ± as long as lower corolla lip, apex acute.		17 U. striatula
+	Trap mouth with a dorsal flabellate appendage; corolla spur cylindric, much shorter than lower corolla lip, apex obtuse		(15)
15 (14)	Middle lobe of lower corolla lip rounded; spur ca. 2 × as long as upper calyx lobe.		16 U. salwinensis
+	Middle lobe of lower corolla lip emarginate; spur as long as or slightly longer than upper calyx lobe		(16)
16 (15)	Lower corolla lip 5-lobed; seed papillae short, obtuse, tufts of sometimes long bristles at both ends; leaf blade membranous.		14 U. kumaonensis
+	Lower corolla lip 3-lobed; seed papillae relatively long, acute, a tuft of short bristles at distal end only; leaf blade fleshy.		15 U. multicaulis
17 (9)	Bracteoles similar to or slightly narrower than bracts		(18)
+	Bracteoles much less than 1/4 as wide as bracts		(21)
18 (17)	Scales present		(19)
+	Scales absent		(20)
19 (18)	Inflorescences and calyx glabrous; plants annual.		1 U. minutissima
+	Inflorescences and calyx ± densely covered with multicellular hairs; plants perennial.		2 U. hirta
20 (18)	Leaves entire; bracts and bracteoles shortly connate to base; corolla yellowish, spur apex obtuse.		10 U. peranomala
+	Larger leaves pinnately divided or lobed, smaller leaves entire; bracts and bracteoles not connate; corolla white, with a yellow dot at throat, spur apex 2-lobed.		11 U. mangshanensis
21 (17)	Corolla yellow		(22)
+	Corolla violet, mauve, lilac, or white		(23)
22 (21)	Peduncle erect; pedicel strongly recurved in fruit; upper calyx lobe shorter than upper corolla lip, apex obtuse.		5 U. bifida
+	Peduncle twining to erect; pedicel erect in fruit; upper calyx lobe longer than upper corolla lip, apex shortly acuminate.		8 U. scandens
23 (21)	Peduncle twining; pedicel strongly deflexed in fruit.		9 U. foveolata
+	Peduncle erect; pedicel erect to spreading in fruit		(24)
24 (23)	Fruiting pedicel as long as or shorter than fruiting calyx; calyx lobes suborbicular in fruit; seeds globose, with isodiametric reticulations; leaf blade 2.5-4.5 cm × 1.5-6 mm.		6 U. uliginosa
+	Fruiting pedicel much longer than fruiting calyx; calyx lobes ovate in fruit; seeds ovoid to ellipsoid, with elongate reticulations; leaf blade 0.4-2 cm × 0.8-3 mm.		7 U. graminifolia