1	Leaves basal, appressed to substrate, often 2, rarely 1 or more than 2, often cordate, orbicular, or ovate		(2)
+	Leaves cauline, well spaced or tufted, never appressed to substrate, various in shape but never cordate nor orbicular		(15)
2 (1)	Petals simple		(3)
+	Petals bilobed, anterior lobe sometimes small and obscure		(9)
3 (2)	Flowers white; sepals ciliate or not		(4)
+	Flowers green or greenish white; sepals not ciliate		(5)
4 (3)	Leaves 3 or 4(-6), in a rosette; lip with a conic appendage at base; spur longer than pedicel and ovary.		1 H. delavayi
+	Leaves 2, subopposite; lip lacking an appendage; spur shorter than pedicel and ovary.		2 H. siamensis
5 (3)	Spur 8-13 mm, ca. as long as or longer than ovary; leaves 2-3 × as long as wide.		5 H. humidicola
+	Spur indistinct or 1-7 mm, shorter than ovary; leaves slightly longer than wide		(6)
6 (5)	Stem and ovary pubescent.		3 H. diplonema
+	Stem and ovary glabrous		(7)
7 (6)	Leaves 2, subopposite; spur ca. 7 mm.		6 H. diphylla
+	Leaves 1 or 2, not as above; spur less than 2 mm		(8)
8 (7)	Inflorescence 10-20-flowered; spur ca. 1.5 mm.		4 H. acianthoides
+	Inflorescence 4- or 5-flowered; spur indistinct or absent.		7 H. reniformis
9 (2)	Leaves with yellowish white markings adaxially		(10)
+	Leaves lacking yellowish white markings adaxially		(11)
10 (9)	Leaves thinly textured; sepals ciliate; petals deeply 2-lobed, lower lobe linear, 9(-13) mm.		8 H. fargesii
+	Leaves relatively thickly textured; sepals not ciliate; petals shallowly 2-lobed, lower lobe ca. 0.5 mm.		9 H. wolongensis
11 (9)	Dorsal sepal 3-6(-7) mm; petals not ciliate		(12)
+	Dorsal sepal 7-13 mm; petals ciliate		(13)
12 (11)	Spur 6-9 mm, shorter than pedicel and ovary.		10 H. aitchisonii
+	Spur 11-13 mm, longer than pedicel and ovary.		11 H. balfouriana
13 (11)	Leaves glaucous adaxially; base of peduncle densely pubescent; dorsal sepal 10-13 mm; spur nearly as long as pedicel and ovary.		12 H. glaucifolia
+	Leaves green adaxially; base of peduncle sparsely pubescent or glabrous; dorsal sepal 7-9 mm; spur longer than pedicel and ovary		(14)
14 (13)	Leaves with 5-7 white veins adaxially; lip lacking an appendage in mouth of spur.		13 H. tibetica
+	Leaves with 5-7 green veins adaxially; lip with a conic appendage in mouth of spur.		14 H. szechuanica
15 (1)	Petals bilobed		(16)
+	Petals simple		(23)
16 (15)	Petals shallowly bilobed; lip ± cross-shaped		(17)
+	Petals deeply bilobed; lip not cross-shaped		(18)
17 (16)	Flowers small; petals ca. 4 mm; lateral lobes of lip obovate-oblanceolate, spreading at a right angle to mid-lobe; spur 1.4-1.5 cm, ca. as long as pedicel and ovary.		15 H. schindleri
+	Flowers rather large, petals 5-5.5 mm; lateral lobes of lip linear, spreading at an acute angle to mid-lobe; spur 2.5-3.5 cm, longer than pedicel and ovary.		16 H. linearifolia
18 (16)	Petals usually with 6 or 7 filiform laciniae; lip with many filiform laciniae.		17 H. polytricha
+	Petals and lip lacking filiform laciniae		(19)
19 (18)	Sepals long acuminate or caudate-aristate at apex		(20)
+	Sepals neither long acuminate nor caudate-aristate at apex		(21)
20 (19)	Petals with anterior (lower) lobe ca. 2.5 mm, shorter than posterior (upper) lobe.		18 H. stenopetala
+	Petals with anterior (lower) lobe 18-25 mm, longer than posterior (upper) lobe.		19 H. pantlingiana
21 (19)	Petals and lip not ciliate on margins of lobes; petal lobes of unequal size, with posterior lobe shorter and wider than anterior lobe.		20 H. coultousii
+	Petals and/or lip ciliate, or lip pubescent along apical margins of lobes; petal lobes of equal size		(22)
22 (21)	Petals and lip with ciliate lobes; spur not lobed.		21 H. petelotii
+	Petals lacking ciliate lobes; spur deeply bilobed at apex.		22 H. hosokawae
23 (15)	Lateral lobes of lip with many long laciniae along outside margins		(24)
+	Lateral lobes of lip sometimes serrate but lacking long laciniae along outside margins		(31)
24 (23)	Petals linear, ca. 0.5 mm wide; spur thickened and geniculate-curved near middle.		23 H. medioflexa
+	Petals not linear, 3-8 mm wide; spur not as above		(25)
25 (24)	Petals falcate, subovate, ca. 8 mm wide		(26)
+	Petals oblong or lanceolate, 4-5 mm wide		(28)
26 (25)	Sepals not ciliate; connective ca. 8 mm wide; staminodes spatulate, ca. 2 mm; spur shorter than ovary.		28 H. yuana
+	Sepals ciliate; connective 2-4 mm wide; staminodes elliptic, ca. 1 mm; spur ca. as long as or longer than ovary		(27)
27 (26)	Inflorescence 1-4-flowered; spur 7-8.5 cm, much longer than ovary; connective ca. 2 mm wide.		29 H. intermedia
+	Inflorescence 5- or more flowered; spur 3.5-4 cm, ca. as long as or slightly longer than ovary; connective 3-4 mm wide.		30 H. arietina
28 (25)	Spur 4.5-6.5 cm, much longer than pedicel and ovary.		26 H. davidii
+	Spur 1.7-3.5 cm, shorter than or nearly as long as pedicel and ovary		(29)
29 (28)	Connective 10-12 mm wide.		24 H. limprichtii
+	Connective 2-5 mm wide		(30)
30 (29)	Petals ± hairy adaxially; spur 17-18 mm; connective ca. 2 mm wide.		25 H. pectinata
+	Petals glabrous adaxially; spur 20-35 mm; connective ca. 5 mm wide.		27 H. mairei
31 (23)	Lateral sepals strongly oblique		(32)
+	Lateral sepals not or slightly oblique		(40)
32 (31)	Lip with a ring-shaped or cupular structure, or sometimes a lamella near entrance of spur		(33)
+	Lip lacking a ring-shaped, cupular structure or lamella near entrance of spur		(36)
33 (32)	Lateral lobes of lip much shorter than mid-lobe		(34)
+	Lateral lobes of lip nearly as long as mid-lobe		(35)
34 (33)	Spur 10-17 mm, shorter than pedicel and ovary; petals oblong, 3-4 mm.		36 H. acuifera
+	Spur 20-29 mm, longer than pedicel and ovary; petals narrowly ovate or narrowly elliptic, 4-5 mm.		37 H. linguella
35 (33)	Flowers white, with a brown vein on lateral sepals; spur 20-22 mm, slightly longer than pedicel and ovary.		38 H. rostellifera
+	Flowers red-orange, with pale green sepals, without a brown vein on lateral sepals; spur 11-12 mm, shorter than pedicel and ovary.		39 H. rostrata
36 (32)	Dorsal sepal much smaller than lateral sepals		(37)
+	Dorsal sepal not or slightly smaller than lateral sepals		(38)
37 (36)	Lateral sepals obliquely axe-shaped, ca. 7 × 13 mm; petals ca. 4 mm wide; spur 5-8 cm, pendulous, longer than pedicel and ovary; ovary glabrous.		31 H. commelinifolia
+	Lateral sepals obliquely triangular, ca. 5 × 8 mm; petals ca. 1 mm wide; spur 2-2.2 cm, ca. as long as or shorter than pedicel and ovary; ovary pubescent.		32 H. austrosinensis
38 (36)	Dorsal sepal with 3 serrulate keels on abaxial surface.		33 H. ciliolaris
+	Dorsal sepal without keels on abaxial surface		(39)
39 (38)	Rachis villous on ridges; petals triangular-lanceolate, ca. 6 mm; lip with a conic callus at base; spur 1.6-2 cm, ca. as long as pedicel and ovary.		34 H. hystrix
+	Rachis glabrous; petals linear-lanceolate, 13-15 mm; lip without callus at base; spur 3-6 cm, much longer than pedicel and ovary.		35 H. fordii
40 (31)	Flowers orange to red; lip mid-lobe bilobed.		40 H. rhodocheila
+	Flowers not orange to red; lip or its mid-lobe simple		(41)
41 (40)	Lip often unlobed; spur often absent.		41 H. malintana
+	Lip deeply 3-lobed; spur present		(42)
42 (41)	Lateral lobes of lip broad, subrhombic or suborbicular, apical margin serrate		(43)
+	Lateral lobes of lip narrow, not as above, margins never serrate		(44)
43 (42)	Plants 9-25 cm tall; leaves cordate or ovate; spur 17-20 mm, slightly shorter or nearly as long as pedicel and ovary.		42 H. finetiana
+	Plants 35-87 cm tall; leaves oblong to narrowly elliptic; spur to 4 cm, longer than pedicel and ovary.		43 H. dentata
44 (42)	Mid-lobe of lip suberect or curved upward, apex adnate to tip of hood formed by dorsal sepal and petals		(45)
+	Mid-lobe of lip never suberect or curved upward, apex never adnate to hood formed by dorsal sepal and petals		(46)
45 (44)	Floral bracts shorter than pedicel and ovary; lateral sepals reflexed; spur cylindric, to 21 mm, much longer than pedicel and ovary.		44 H. lucida
+	Floral bracts longer than flower; lateral sepals spreading, not reflexed; spur clavate, 3-6 mm, shorter than pedicel and ovary.		45 H. shweliensis
46 (44)	Leaves tufted at base of stem; spur longer than ovary		(47)
+	Leaves not tufted at base of stem; spur longer or shorter than ovary		(50)
47 (46)	Leaves narrowly elliptic or broadly oblanceolate, 18-20 mm wide; flowers pale green.		46 H. iyoensis
+	Leaves linear or linear-lanceolate, 4-15 mm wide; flowers yellowish green or white		(48)
48 (47)	Leaves 4 or 5, 4-6 mm wide; dorsal sepal ca. 2 mm; spur narrowly cylindric.		47 H. viridiflora
+	Leaves 6-13, 8-15 mm wide; dorsal sepal ca. 5 mm; spur narrowly cylindric-clavate		(49)
49 (48)	Dorsal sepal broadly ovate; lateral sepals narrowly ovate; petals ovate-ligulate; lip with lateral lobes narrower than mid-lobe.		48 H. plurifoliata
+	Dorsal sepal elliptic; lateral sepals elliptic; petals linear; lip with lateral lobes and mid-lobe equal in width.		49 H. tonkinensis
50 (46)	Dorsal sepal 7-8 mm		(51)
+	Dorsal sepal 3-4 mm		(52)
51 (50)	Spur narrowly cylindric, 3-5 mm, shorter than pedicel and ovary; dorsal sepal narrowly ovate, ca. 4 mm wide; petals ca. 2.5 mm wide; flowers yellow.		50 H. fulva
+	Spur clavate, 8-13 mm, ca. as long as pedicel and ovary; dorsal sepal cordate or broadly ovate, 5-6 mm wide; petals obliquely ovate-triangular, 3-3.8 mm wide; flowers yellowish green.		51 H. marginata
52 (50)	Floral bracts longer than ovary; flowers pale yellowish green.		52 H. leptoloba
+	Floral bracts shorter or nearly as long as ovary; flowers pinkish white or pale green		(53)
53 (52)	Floral bracts much shorter than pedicel and ovary; flowers pinkish white; lateral sepals 2-veined; petals obliquely oblong-ovate; spur ca. 21 mm.		53 H. nematocerata
+	Floral bracts nearly as long as pedicel and ovary; flowers pale green; lateral sepals 3-veined; petals lanceolate; spur ca. 17 mm.		54 H. furcifera