1	Corollas ± salverform, (funnelform-salverform in I. thurberi; limb sometimes ± campanulate in I. muricata and I. setosa).		(2)
+	Corollas funnelform.		(14)
2 (1)	Flowers diurnal (open all day); corollas usually orange, red, red and yellow, or red-orange, sometimes white (cultivars of I. coccinea and I. quamoclit), 14–50 mm.		(3)
+	Flowers nocturnal (open dusk to early morning); corollas usually lavender, pink, or white, tubes sometimes purple to red, limbs or throats sometimes purple, red, or with green or yellowish bands or lines, 30–150 mm.		(8)
3 (2)	Perennials; corollas red		1 Ipomoea microdactyla
+	Annuals; corollas usually red, red and yellow, or red-orange, sometimes white (cultivars of I. coccinea and I. quamoclit).		(4)
4 (3)	Leaf blades palmati-pinnate or pinnatisect.		(5)
+	Leaf blades not palmati-pinnate or pinnatisect.		(6)
5 (4)	Leaf blades palmati-pinnate, lobes 7–11+		2 Ipomoea sloteri
+	Leaf blades pinnatisect, lobes 19–41+		3 Ipomoea quamoclit
6 (4)	Sepals ± equal, 4–4.5 mm		4 Ipomoea hederifolia
+	Sepals unequal, outers 3–3.5 mm, inners 4–5.7 mm.		(7)
7 (6)	Leaf blades usually cordate, sometimes ovate, sagittate, or triangular		5 Ipomoea coccinea
+	Leaf blades usually (3–)5–7-lobed, middle lobe narrowly ± rhombic, sometimes proximal blades cordate to ovate, not lobed		6 Ipomoea cristulata
8 (2)	Leaf blades usually palmatisect, sometimes sagittate.		(9)
+	Leaf blades cordate, orbiculate, ovate, triangular, triangular-ovate, or 3–5(–7)-lobed.		(10)
9 (8)	Sepals 5–12 mm; corolla limbs 30–36 mm diam.		7 Ipomoea tenuiloba (in part)
+	Sepals 12–15 mm; corolla limbs 50–65 mm diam.		8 Ipomoea thurberi
10 (8)	Leaf blade surfaces: abaxial tomentulose, adaxial glabrous; corollas white, throat lavender to purple inside		9 Ipomoea macrorhiza
+	Leaf blade surfaces glabrous or hairy, not tomentulose; corollas usually lavender, pink, or white, sometimes with green or yellowish bands or lines.		(11)
11 (10)	Sepal apices acute, outers each with ± corniform appendage.		(12)
+	Sepal apices emarginate, obtuse, or truncate, none with corniform appendages.		(13)
12 (11)	Corollas white, throat green-banded inside; fruits 20–30 mm		10 Ipomoea alba
+	Corollas white, turning lavender; fruits 18–20 mm		11 Ipomoea muricata
13 (11)	Stems ± setose; corollas lavender or pink		12 Ipomoea setosa
+	Stems not setose; corollas white, limb with yellowish lines		13 Ipomoea violacea
14 (1)	Peduncles usually hairy and hairs usually ± antrorse, retrorse, or spreading, rarely appressed, rarely glabrous or glabrate (I. barbatisepala and I. indica); sepals herbaceous.		(15)
+	Peduncles usually glabrous or hairy and hairs appressed, sometimes puberulent (I. carnea), sparsely hispidulous (I. costellata), pilosulous on proximal 1–2 mm and otherwise glabrous (I. dumetorum), or setose; sepals usually chartaceous or coriaceous, sometimes herbaceous or membranous.		(21)
15 (14)	Perennials.		(16)
+	Annuals.		(18)
16 (15)	Leaf blade surfaces glabrous or ± pilose; sepals glabrous or abaxial surface sparsely hairy, hairs appressed		14 Ipomoea indica
+	Leaf blade surfaces ± hirsute or sericeous; sepal surfaces: abaxial ± hispid or sericeous.		(17)
17 (16)	Leaf blades broadly ovate to reniform, usually 3–5(–7)-lobed; sepals 18–30 mm		15 Ipomoea lindheimeri
+	Leaf blades cordate, ovate, or 3–5-lobed; sepals 9–21 mm		16 Ipomoea pubescens
18 (15)	Leaf blades (3–)5–7-lobed, palmatisect (incised nearly to petiole tip)		17 Ipomoea barbatisepala
+	Leaf blades cordate, orbiculate, ovate, or 3(–5)-lobed, not palmatisect.		(19)
19 (18)	Sepals elliptic, lance-oblong, or oblong, 8–15 mm, narrowed distal portion shorter to slightly longer than dilated base		18 Ipomoea purpurea
+	Sepals ± lanceolate or lance-linear, 12–30 mm, narrowed distal portion notably longer than dilated base.		(20)
20 (19)	Sepals ± lanceolate, 12–24 mm, proximally ovate, abruptly narrowed to ± curved or spreading distal portion; corollas 20–37(–45) mm		19 Ipomoea hederacea
+	Sepals lance-linear, 15–25(–30) mm, proximally narrowly ovate, grad­ually narrowed to ± straight distal portion; corollas (20–)30–60+ mm		20 Ipomoea nil
21 (14)	Stems usually repent, (rooting at nodes), rarely twining.		(22)
+	Stems not repent.		(25)
22 (21)	Leaf blades hastate, lanceolate, linear, oblong, ovate, or ± 3–5-lobed; corollas usu­ally purple or white, throat sometimes purplish or yellow inside.		(23)
+	Leaf blades cordate, ± orbiculate, ovate, reniform, or rounded-cordate; corollas usually lavender, pink, or red, rarely white, throat sometimes darker inside.		(24)
23 (22)	Sepals elliptic-ovate to oblong-ovate, 6–8 mm, ± equal; corollas usually purple, rarely white		21 Ipomoea aquatica
+	Sepals lance-oblong, 10–15 mm, unequal; corollas white, throat usually yellow, sometimes purplish, inside		22 Ipomoea imperati
24 (22)	Leaf blade apices acute to rounded; corollas usually red, rarely white, 50–80 mm		23 Ipomoea asarifolia
+	Leaf blade apices ± emarginate; corollas lavender or pink, 35–40(–70) mm		24 Ipomoea pescaprae
25 (21)	Stems usually erect, sometimes ± trailing (I. leptophylla).		(26)
+	Stems usually trailing, twining, or twining only near tips, rarely ascending, decum­bent, or erect.		(27)
26 (25)	Shrubs; leaf blades 40–170 mm wide, bases cordate or ± truncate		25 Ipomoea carnea
+	Perennials; leaf blades 2–8(–10) mm wide, bases ± cuneate		26 Ipomoea leptophylla
27 (25)	Leaf blades cuneate-obovate and distally ± incised, 3–5(–7+)-toothed		27 Ipomoea plummerae (in part)
+	Leaf blades not cuneate-obovate and distally incised.		(28)
28 (27)	Leaf blades palmatisect (incised ± to petiole tip), lobes (3–)5–9+, usually filiform, lance-linear, lanceolate, linear, or narrowly oblanceolate to spat­ulate, sometimes elliptic, lance-elliptic, or lance-ovate.		(29)
+	Leaf blades not palmatisect, sometimes palmately lobed.		(35)
29 (28)	Annuals.		(30)
+	Perennials.		(32)
30 (29)	Corollas 10–12 mm		28 Ipomoea costellata
+	Corollas 18–30(–40) mm.		(31)
31 (30)	Leaf blade lobes 5–7(–9), usually filiform to linear, sometimes lance-linear, 0.2–2(–5) mm wide		29 Ipomoea ternifolia
+	Leaf blade lobes 5, lance-linear to lanceolate, (5–)10–15(–20) mm wide		30 Ipomoea wrightii
32 (29)	Leaf blade lobes 5 (proximal 2 lobes sometimes 2-lobed), lance-elliptic, lanceolate, or lance-ovate, (3–)8–15(–30) mm wide		31 Ipomoea cairica
+	Leaf blade lobes (3–)5–9, filiform, lanceolate, linear, or spatulate, 0.2–2.5(–6.5) mm wide.		(33)
33 (32)	Corollas white (limb sometimes purple or pale rose), 35–65 mm		7 Ipomoea tenuiloba (in part)
+	Corollas lavender, purple, or red-purple, 25–40 mm.		(34)
34 (33)	Stems usually ± trailing, sometimes ascending, erect, or twining near tips; leaf blade lobes 3–30(–50) × (0.5–)1–2.5 mm		27 Ipomoea plummerae (in part)
+	Stems usually ascending to erect, sometimes trailing; leaf blade lobes (3–)5–15(–25) × 0.2–1 mm		32 Ipomoea capillacea
35 (28)	Corollas usually blue (drying pink or purple), sometimes white, some­times throat white outside and yellow inside.		(36)
+	Corollas lavender, lavender-pink, lilac, pink, pink-purple, purple, purplish, red-purple, or ± white, throat sometimes darker inside.		(37)
36 (35)	Corollas 26–27 mm, limb 30–35 mm diam.		33 Ipomoea cardiophylla
+	Corollas 35–60 mm, limb 50–90 mm diam.		34 Ipomoea tricolor
37 (35)	Sepals dotted with dark spots on abaxial surface		35 Ipomoea dumetorum
+	Sepals not dotted with dark spots.		(38)
38 (37)	Leaf blades usually hastate or sagittate, ± triangular, sometimes ovate.		(39)
+	Leaf blades usually cordate, cordate-ovate, deltate-ovate, lance-oblong, lanceolate, lance-ovate, linear, oblong-ovate, orbiculate, ovate, pandurate, or reniform, some­times 3–5(–7)-lobed.		(40)
39 (38)	Leaf blade surfaces glabrous; sepals elliptic, oblong, or ovate, 8–9 mm; corollas 60–90 mm		36 Ipomoea sagittata
+	Leaf blade surfaces ± hairy, adaxial sometimes glabrate; sepals lance-oblong, lanceolate, or lance-ovate, 5–8 mm; corollas 30–45 mm		37 Ipomoea tenuissima
40 (38)	Annuals; corollas 6–20(–25) mm.		(41)
+	Perennials; corollas 18–100 mm.		(43)
41 (40)	Sepals 6–7 mm, apices acute or obtuse		38 Ipomoea triloba
+	Sepals (8–)11–14 mm, apices acuminate.		(42)
42 (41)	Corollas white, 15–20(–25) mm; fruits 10–13 mm diam.		39 Ipomoea lacunosa
+	Corollas lavender or white, 6–15(–20) mm; fruits 7–8 mm diam.		40 Ipomoea × leucantha
43 (40)	Sepals 4–5.5 mm		41 Ipomoea amnicola
+	Sepals 8–22 mm.		(44)
44 (43)	Corollas 20–38 mm		42 Ipomoea cordatotriloba
+	Corollas (30–)40–100 mm.		(45)
45 (44)	Corollas usually lavender, lavender-pink, pink, or purple, some­times white, throat usually darker inside.		(46)
+	Corollas pink or ± white, throat lavender, purple, purple-red, or red inside.		(47)
46 (45)	Leaf blade bases cordate; corollas (30–)40–70 mm; seeds glabrous		43 Ipomoea batatas
+	Leaf blade bases cordate-hastate; corollas 70–90 mm; seeds hairy		44 Ipomoea rupicola
47 (45)	Leaf blades cordate, cordate-ovate, or pandurate		45 Ipomoea pandurata
+	Leaf blades deltate-ovate, lance-oblong, lanceolate, lance-ovate, or linear.		(48)
48 (47)	Leaf blades lance-oblong, lanceolate, or linear, 100–120(–210) mm; Arizona		46 Ipomoea longifolia
+	Leaf blades deltate-ovate or narrowly lance-ovate, 30–80 mm; Kansas, Oklahoma, Texas		47 Ipomoea shumardiana