1	Leaves 3-veined from base		2 Hoya pottsii
+	Leaves pinnately veined, or veins obscure.		(2)
2 (1)	Inflorescences 4- or 5-flowered, terminal; leaves 1-1.5 cm		32 Hoya chinghungensis
+	Inflorescences many flowered, usually extra-axillary, rarely terminal (H. lii); leaves more than 2 cm.		(3)
3 (2)	Outer angle of corona lobes rounded.		(4)
+	Outer angle of corona lobes acute.		(13)
4 (3)	Leaves villous or pubescent.		(5)
+	Leaves glabrous.		(6)
5 (4)	Leaf blade broadly oblong or long quadrate, villous, apex mucronate; corolla lobes as long as tube		23 Hoya villosa
+	Leaf blade elliptic, oblong, elliptic-lanceolate, or rarely suborbicular, pubescent, apex short acuminate to obtuse; corolla lobes longer than tube		24 Hoya lyi
6 (4)	Leaf blade orbicular to widest above middle, 3-6 cm wide.		(7)
+	Leaf blade of other shapes, if more than 3 cm wide then widest below middle.		(9)
7 (6)	Leaf blade spatulate to oblanceolate, 10-21 cm, lateral veins 10 or more pairs; flower clusters flat topped; corolla white with purple spots		21 Hoya radicalis
+	Leaf blade obovate to orbicular, 4-8 cm, lateral veins ca. 4 pairs or obscure; flower clusters globose; corolla uniformly white.		(8)
8 (7)	Apex of leaf blade retuse or concave, lateral veins obscure		20 Hoya kerrii
+	Apex of leaf blade entire, lateral veins conspicuous, ca. 4 pairs		22 Hoya liangii
9 (6)	Leaf blades often pandurate, sometimes oblong; peduncle 0.3 cm; corolla yellow or reddish		27 Hoya pandurata
+	Leaf blade lanceolate or oblong-lanceolate to oblong-oblanceolate; peduncle 1-8 cm; corolla white.		(10)
10 (9)	Branchlets and petiole hairy; peduncle 1-4 cm; corolla reflexed; corona lobes erect.		(11)
+	Branchlets and petiole glabrous; peduncle 5-8 cm; corolla rotate; corona lobes spreading-stellate.		(12)
11 (10)	Branchlets and petiole setose; lateral veins of leaf blade conspicuous adaxially; inflorescences terminal		25 Hoya lii
+	Branchlets and petiole minutely puberulent at least when young; lateral veins of leaf blade ill defined adaxially; inflorescences extra-axillary		26 Hoya mekongensis
12 (10)	Leaf blade 1.5-2 cm wide; flower clusters flat topped; corolla 1-1.5 cm in diam., villous inside		28 Hoya mengtzeensis
+	Leaf blade 2.5-4.5 cm wide; flower clusters globose; corolla ca. 3 cm in diam., obscurely puberulent inside		29 Hoya griffithii
13 (3)	Corolla purple; inflorescences on hanging leafless branches (leaves not known)		11 Hoya commutata
+	Corolla white, pink, yellow, or yellowish; inflorescences always on normal leafy branches.		(14)
14 (13)	Leaf blade linear, 0.4-0.7 cm wide.		(15)
+	Leaf blade not linear, 1-6.5 cm wide.		(16)
15 (14)	Leaf blade 2.5-5 cm, hirsute abaxially; inflorescences terminal; corolla lobes glabrous		31 Hoya linearis
+	Leaf blade 10-20 cm, glabrous; inflorescences extra-axillary; corolla lobes pubescent		30 Hoya longifolia
16 (14)	Corolla strongly reflexed; corona distinctly stalked, lobes spurred at base		1 Hoya multiflora
+	Corolla not reflexed; corona sessile, lobes not spurred.		(17)
17 (16)	Leaf apex caudate; flowers yellow or yellowish.		(18)
+	Leaf apex obtuse to acuminate; flowers white or reddish.		(20)
18 (17)	Leaf blade 4.5-7 cm, base rounded, lateral veins 4 or 5 pairs, obscure; peduncle ca. 0.4 cm; pedicel 1-1.2 cm; corolla lobes glabrous		5 Hoya lasiogynostegia
+	Leaf blade 9-13 cm, base cuneate, lateral veins 10-12 pairs, conspicuous; peduncle 1.5-2.5 cm; pedicel 2-2.5 cm; corolla lobes puberulent inside.		(19)
19 (18)	Leaf blade symmetrical at base, lateral veins at right angle to midvein, uniformly colored		3 Hoya fusca
+	Leaf blade oblique at base, lateral veins obliquely ascending, midrib with pale zone on both sides		4 Hoya lipoensis
20 (17)	Lateral veins of leaf blade obscure or obsolete.		(21)
+	Lateral veins of leaf blade conspicuous.		(26)
21 (20)	Leaf blade oblong or widest above middle.		(22)
+	Leaf blade widest below middle.		(23)
22 (21)	Petiole and abaxial surface of leaf blade pubescent; corolla ca. 1.2 cm in diam.		6 Hoya thomsonii
+	Petiole and leaf blade glabrous; corolla 2-4 cm in diam.		30 Hoya longifolia
23 (21)	Pedicel longer than peduncle.		(24)
+	Pedicel shorter than or as long as peduncle.		(25)
24 (23)	Leaf blade lanceolate to ovate-lanceolate, apex acuminate; peduncle 1-5 cm; sepals puberulent outside		7 Hoya siamica
+	Leaf blade elliptic or elliptic-oblong, apex obtuse; peduncle ca. 0.3 cm; sepals glabrous outside		8 Hoya revolubilis
25 (23)	Corolla 0.6-0.7 cm wide, violet dotted, base conspicuously white villous inside, lobes much longer than tube		9 Hoya lacunosa
+	Corolla 1.5-2 cm wide, not violet dotted, densely papillate inside, lobes as long as tube		10 Hoya carnosa
26 (20)	Flower clusters flat topped.		(27)
+	Flower clusters globose.		(28)
27 (26)	Leaf blade cordate at base; petiole and abaxial side of midvein puberulent; peduncle shorter than pedicel; calyx outside and corolla puberulent		12 Hoya cordata
+	Leaf blade rounded at base; petiole and midvein glabrous; peduncle much longer than pedicel; calyx and corolla glabrous		13 Hoya nervosa
28 (26)	Petiole up to 0.4 cm.		(29)
+	Petiole 1-3 cm.		(30)
29 (28)	Lateral leaf veins numerous, parallel; peduncle shorter than pedicel; corolla lobes papillate inside		14 Hoya polyneura
+	Lateral leaf veins 4 or 5 pairs, not parallel; peduncle longer than pedicel; corolla mealy inside		15 Hoya dasyantha
30 (28)	Leaves pubescent abaxially, especially along veins.		(31)
+	Leaves glabrous.		(32)
31 (30)	Leaf blade short acuminate at apex, cuneate at base; calyx glabrous; corolla ca. 1 cm in diam.		16 Hoya silvatica
+	Leaf blade obtuse or rounded at apex, rounded or broadly cuneate at base; calyx puberulent outside; corolla ca. 1.5 cm in diam.		17 Hoya salweenica
32 (30)	Lateral leaf veins ca. 7 pairs; peduncle to 5 cm; calyx pubescent outside; corolla densely pale scurfy inside		18 Hoya fungii
+	Lateral leaf veins ca. 4 pairs; peduncle ca. 2 cm; calyx glabrous; corolla sparsely pubescent inside		19 Hoya ovalifolia