1	Plants parasitic (lacking chlorophyll)		1 Cuscuta, p. 271
+	Plants not parasitic (autotrophic).		(2)
2 (1)	Stems usually ascending, creeping, decumbent, erect, procumbent, prostrate, or trailing, seldom twining-climbing; leaves: larger blades 10–30(–100) mm; styles usually 2 (1 in Convolvulus).		(3)
+	Stems usually twining-climbing, sometimes repent or trailing, rarely almost absent, ascending, decumbent, erect, or procumbent; leaves: larger blades (10–)40–270 mm; styles 1.		(9)
3 (2)	Stigmas or stigma lobes cylindric, linear, filiform, subclavate, subulate, or spatulate.		(4)
+	Stigmas capitate, globose, or peltate.		(5)
4 (3)	Leaves sessile or subsessile; styles 2, stigma lobes 4, filiform to subclavate		2 Evolvulus, p. 303
+	Leaves usually petiolate, rarely sessile; styles 1, stigma lobes 2, cylindric, linear, or spatulate		14 Convolvulus (in part), p. 336
5 (3)	Styles: insertion ± basal; fruits subglobose to ± compressed, ± incised and 2-lobed, indehiscent or shattering irregularly		3 Dichondra, p. 306
+	Styles: insertion not ± basal; fruits conic, fusiform, globose, oblong-ovoid, or ovoid, dehiscence valvate.		(6)
6 (5)	Leaf blades 1–14 mm.		(7)
+	Leaf blades (1–)10–60(–100).		(8)
7 (6)	Stems decumbent to erect, seldom, if ever, mat-forming; corollas salverform, white, 5–7 mm		4 Cressa, p. 308
+	Stems decumbent, erect, prostrate, or trailing, sometimes mat-forming; corollas ± campanulate, greenish yellow to yellow, 3–4 mm		5 Petrogenia, p. 310
8 (6)	Sepals 9–28 mm; corollas blue, blue-purple, or white with blue limb, 35–85 mm		6 Bonamia, p. 310
+	Sepals 4–11 mm; corollas usually white, sometimes lavender, maroon, pink, purple, or red, 8–25 mm		7 Stylisma, p. 311
9 (2)	Fruits indehiscent.		(10)
+	Fruits dehiscent.		(13)
10 (9)	Sepals lanceolate-linear, 1–2 mm; corollas white, to 8 mm		8 Poranopsis, p. 314
+	Sepals elliptic, oblong, or ovate to orbiculate, 7–20 mm; corollas lavender, purple, purplish red, red, white, or yellow, 25–95 mm.		(11)
11 (10)	Leaf blade abaxial surfaces black-glandular-punctate; fruits dry, 25–30 mm		9 Stictocardia, p. 315
+	Leaf blade abaxial surfaces glabrous, glabrate, or white-hairy; fruits fleshy or dry, 10–15 mm.		(12)
12 (11)	Leaf blades 180–270 mm; sepals ovate, 15–20 mm; corollas lavender, 60–65 mm; fruits berrylike, fleshy		10 Argyreia, p. 316
+	Leaf blades 40–100 mm; sepals oblong, 7–12 mm; corollas proximally purplish, distally ± white with greenish bands, 25–40 mm; fruits capsular or nutlike, dry		11 Turbina, p. 317
13 (9)	Stigmas or stigma lobes cylindric, elliptic, linear, oblong, reniform, spatulate, or subulate.		(14)
+	Stigmas or stigma lobes capitate or globose.		(16)
14 (13)	Stems hairy, hairs usually branched, glandular, and/or stellate, sometimes simple		12 Jacquemontia, p. 317
+	Stems glabrous or hairy, hairs not branched, glandular, or stellate.		(15)
15 (14)	Sepals (5–)8–15(–25) mm; ovary 1-locular; stigma lobes linear to oblong, apices blunt		13 Calystegia, p. 321
+	Sepals 3–12 mm; ovary 2-locular; stigma lobes cylindric to spatulate, apices acute.		14 Convolvulus (in part), p. 336
16 (13)	Fruit dehiscence circumscissile		15 Operculina, p. 338
+	Fruit dehiscence irregular or valvate.		(17)
17 (16)	Anthers twisted after dehiscence; pollen usually 3–9-colpate, rarely aggrecolpate, not echinate		16 Merremia, p. 339
+	Anthers straight after dehiscence; pollen rugate and not echinate (Aniseia) or pantoporate and echinate (Ipomoea).		(18)
18 (17)	Sepals notably accrescent in fruit, outer 3 notably longer than inner 2; corolla white, campanulate, 25–30 mm		17 Aniseia, p. 342
+	Sepals seldom notably accrescent in fruit, outer 3 not notably longer than inner 2; corolla usually blue, lavender, pink, purple, red, violet, or white, sometimes orange, red and yel­low, or red-orange, usually funnelform, sometimes campanulate or salverform, (6–)20–80(–150+) mm		18 Ipomoea, p. 342