1	"Anther easily removed, cap-like, incumbent, bent downwards through 90–120° (except in Oberonia); plants mostly epiphytes or epiliths, or less commonly climbers or terrestrial herbs; tuberoids absent although roots or rhizomes fleshy in some terrestrial taxa; pseudobulbs often present; inflorescences lateral or terminal."	2
1	"Anther persistent, not cap-like, erect, parallel to the axis of the column or bent downwards through less than 90° ; plants growing in soil or very rarely humus-epiphytes or humus-epiliths; tuberoids often present; pseudobulbs absent; inflorescences terminal."	24
2	"Climbing plants with stems arising from the ground; seeds winged."	3
2	"Plants not climbing (sometimes creeping epiphytes appear to be climbing); seeds not winged."	4
3	"Leaves ovate, 3–6 cm long; labellum with numerous transverse, parallel ridges on both sides of median ridge, not warty; column with a short, descending foot, tapering into the median ridge of the labellum."	Erythrorchis
3	"Leaves triangular, less than 2.5 cm long; labellum without ridges but with most of its surface densely warty; column footless."	Pseudovanilla
4	"Plants with leaves reduced to scales."	5
4	"Plants with well-developed green leaves."	9
5	"Plants epiphytic or epilithic; roots creeping over surface of host; flowers less than 5 mm long."	6
5	"Plants terrestrial; roots subterranean; flowers more than 5 mm long."	7
6	"Stems creeping, consisting of globose pseudobulbs, connected by filiform rhizomes."	Bulbophyllum
6	"Stems almost vestigial, not creeping, not differentiated into pseudobulbs and rhizomes."	Taeniophyllum
7	"Sepals and lateral petals fused into a tube; flowers not resupinate, the labellum being the uppermost perianth segment."	Gastrodia
7	"Sepals and lateral petals free; flowers resupinate."	8
8	"Labellum with a prominent basal spur, free, glabrous."	Epipogium
8	"Labellum without a spur, fused to the base of the column, hairy on the upper surface."	Dipodium
9	"Leaves pleated, thin; plant growing in soil."	10
9	"Leaves conduplicate or laterally flattened, thin to leathery or succulent; plant epiphytic, epilithic or rarely growing in soil."	14
10	"Dorsal sepal 3–6 cm long; sepals and lateral petals white on the outside, brown on the inside."	Phaius
10	"Dorsal sepal 0.5–1.9 cm long; sepals and lateral petals not as above."	11
11	"Labellum with a hollow spur protruding backwards, with a deeply 4-lobed lamina."	Calanthe
11	"Labellum lacking a hollow spur, with unlobed or obscurely 3-lobed or deeply 2-lobed lamina."	12
12	"Inflorescence axis erect basally but abruptly curved over towards the tip at flowering time, terete; flowers pink; labellum shallowly saccate."	Geodorum
12	"Inflorescence axis completely erect, square in cross-section; flowers yellow-green to reddish purple; labellum not saccate."	13
13	"Fleshy stems held above ground; lateral sepals free."	Diteilis
13	"Fleshy stems subterranean; lateral sepals partly connate along adjacent margins."	Empusa
14	"Sepals and petals less than 1 mm long; leaves laterally flattened; flowers arranged in loose whorls in the inflorescence."	Oberonia
14	"Sepals and petals more than 1 mm long; leaves dorsiventrally flattened to terete; flowers not whorled."	15
15	"Labellum not saccate, lacking a hollow spur, attached to the base of the footless column."	16
15	"Labellum saccate and/or possessing a hollow spur and/or attached to the tip of a prominent column foot."	17
16	"Inflorescences lateral; sepals 4–10 mm wide."	Cymbidium
16	"Inflorescences terminal; sepals 1–3 mm wide."	Cestichis
17	"Growth sympodial; stems often swollen to form pseudobulbs; lateral sepals basally fused to the prominent column foot to form a mentum."	18
17	"Growth monopodial; stems never swollen; lateral sepals free; column foot present or absent."	19
18	"Stems either not differentiated into rhizome and pseudobulb, or if so differentiated then pseudobulb composed of more than just the most apical internode; each stem with 1–6 leaves at its apex."	Dendrobium
18	"Stems differentiated into rhizome and pseudobulb; pseudobulb composed of only the most apical internode; each pseudobulb with 1 leaf at apex."	Bulbophyllum
19	"Roots strongly tuberculate, rough; sepals and lateral petals more than 10 times longer than broad, filiform; flowers lasting less than 2 days."	Rhinerrhiza
19	"Roots smooth; sepals and lateral petals less than 10 times longer than broad, not filiform; flowers lasting more than 2 days."	20
20	"Labellum shallowly saccate, and sometimes with a solid, forward-pointing spur."	21
20	"Labellum with a prominent, hollow, backward-pointing spur."	22
21	"Labellum with a hollow pouch at its front; inflorescence 1–25-flowered."	Sarcochilus
21	"Labellum with a hollow pouch at its rear; inflorescence 25–75-flowered."	Peristeranthus
22	"Labellum spur lacking calli; labellum midlobe papillose."	Papillilabium
22	"Labellum spur with calli arising inside or overhanging its mouth; labellum midlobe not papillose."	23
23	"Labellum spur without internal calli but thickened base of midlobe extended part way across the orifice of the spur in the form of a broad, 2-fid callus."	Schistotylus
23	"Labellum spur with a finger-like callus arising from the upper anterior wall and directed towards its apex."	Plectorrhiza
24	"Inflorescence a dense capitulum with only the flowers and involucral bracts emerging above the soil surface, the peduncle and the rest of the plant entirely subterranean."	Rhizanthella
24	"Inflorescence racemose or spicate or 1-flowered, mostly or wholly above the soil surface."	25
25	"Flowers not resupinate, the labellum positioned above the column."	26
25	"Flowers resupinate, the labellum positioned below the column."	31
26	"Column almost as long as dorsal sepal."	27
26	"Column much shorter than dorsal sepal."	29
27	"Column wings discontinuous, 4-lobed; labellum passively motile on basal hinge; leaves absent or 2—6 on a lateral shoot."	Arthrochilus
27	"Column wings continuous, the whole column deeply concave; labellum actively motile, elastic, irritable, upcurved when set, recurved when sprung; leaf solitary, basal."	28
28	"Surface of labellum lamina smooth; column foot absent."	Caleana
28	"Surface of labellum lamina warty; column foot present, separating the points of insertion of the labellum and lateral sepals from those of the dorsal sepal and lateral petals."	Paracaleana
29	"Leaves narrow-elliptic to narrow-ovate, lamina flat, petiolate, connected to rhizome separately from the inflorescence or absent; labellum several times broader than sepals and lateral petals; plant lacking tuberoids, with fleshy roots."	Cryptostylis
29	"Leaf linear, terete, tubular, enclosing inflorescence basally or rarely absent; labellum 1–2 times as broad as sepals and lateral petals; plant with paired tuberoids."	30
30	"Labellum articulate on a conspicuous claw, mobile; free apical part of leaf flattened."	Genoplesium
30	"Labellum sessile at the base of the column, immobile; free apical part of leaf terete."	Prasophyllum
31	"Stem differentiated into the erect, flowering shoot and succulent, creeping rhizome which is either rootless or which bears wiry roots at its nodes; tuberoids absent; stigma in 2 lateral parts, at the base of the deeply cleft rostellum."	32
31	"Stem not differentiated into erect and creeping parts (except in Adenochilus), not succulent; plants with tuberoids or less frequently with fleshy roots or lacking fleshy subterranean structures; stigma entire."	33
32	"Petals fused to dorsal sepal, forming a hood over the column; lateral sepals free; roots present; rhizome not constricted."	Zeuxine
32	"Petals free; sepals fused for about half their length to form a tube; roots absent; rhizome conspicuously constricted at the nodes."	Cheirostylis
33	"Lateral petals linear, 5–10 times narrower than lateral sepals; stigma sunk in a deep cavity that is partially covered by 2 flaps of the anther lid and a fleshy flap that is the lower margin of the stigma."	Eriochilus
33	"Lateral petals slightly broader to slightly narrower than lateral sepals; stigma not as above."	34
34	"Flowering shoot leafless, but may have short acute leaf-like bracts."	35
34	"Flowering shoot with 1 or more prominently developed leaves."	37
35	"Dorsal sepal and lateral petals adherent, forming a hood."	Pterostylis
35	"Dorsal sepal and lateral petals free."	36
36	"Labellum densely covered by a beard of long, hair-like calli; column about a fifth as long as labellum."	Calochilus
36	"Labellum with knob-like calli; column about half as long as labellum."	Burnettia
37	"Flowering shoot with a single, well-developed leaf that is much larger than the other, scale-like, foliar organs."	38
37	"Flowering shoot with 2 or more well-developed leaves of similar size."	52
38	"Leaf cordate, heart-shaped or reniform, held horizontally."	39
38	"Leaf not cordate, ovate to linear."	44
39	"Inflorescence consisting of a solitary, sessile flower; flower dominated by the labellum and hood-like dorsal sepal; lateral petals and sepals minute."	Corybas
39	"Inflorescence pedunculate, 1–many-flowered."	40
40	"Leaf basal, ground-hugging."	41
40	"Leaf cauline, held horizontally above ground level."	42
41	"Labellum unlobed, almost flat, pinkish brown; plant not turning black on drying."	Cyrtostylis
41	"Labellum shallowly 3-lobed, the lateral lobes erect, white with prominent red stripes; plant turning black on drying."	Pyrorchis
42	"Flower predominantly white; labellum 3-lobed, with a dense, central band of numerous, yellow, clubbed calli; plant rhizomatous, lacking tubers."	Adenochilus
42	"Flower predominantly green to brown or purplish; labellum unlobed (but sometimes coarsely toothed), with a central plate-like or channelled callus and sometimes with 2 basal, gland-like calli; plant tuberous."	43
43	"Leaf green on undersurface, often deeply lobed; labellum coarsely toothed, lacking distinct, basal, gland-like calli."	Acianthella
43	"Leaf with purple pigmentation on undersurface, entire; labellum entire, with two basal, gland-like calli."	Acianthus
44	"Leaf at least sparsely hairy."	45
44	"Leaf glabrous."	48
45	"Labellum with only 1 or 2 basal calli."	Glossodia
45	"Labellum with more than 2 calli."	46
46	"Tubers partially encased in a few-layered tunic; flowers predominantly white, pink, yellow, red, brown or green."	Caladenia
46	"Tubers entirely encased in a multilayered tunic; flowers predominantly blue."	47
47	"Labellum prominently 3-lobed, with 2 central rows of white or yellow calli."	Cyanicula
47	"Labellum scarcely 3-lobed, with 4–6 rows of calli that are blue on the midlobe but white more basally."	Pheladenia
48	"Leaf linear, terete, tubular, enclosing inflorescence basally; dorsal sepal less than 3 mm long; flowers uniformly green."	Microtis
48	"Leaf linear to ovate, flat or channelled; dorsal sepal more than 3 mm long; flowers variously coloured but rarely uniformly green."	49
49	"Column not hooded nor collared; labellum 3-lobed, concave."	50
49	"Column hooded or collared (with a mitra); labellum not lobed, flat."	51
50	"Inflorescence 1-flowered; column wings prominent, extending beyond the anther; plant lacking tubers."	Adenochilus
50	"Inflorescence usually 2–8-flowered; column wings reduced, not exceeding anther; plant tuberous."	Lyperanthus
51	"Labellum usually densely covered by a beard of long, hair-like calli, or very rarely lacking calli but then column with 2 basal, lateral, dark glands; base of column with prominent ridged collar."	Calochilus
51	"Labellum lacking calli, similar to lateral petals; column lacking basal, lateral glands; top of column ornamented by prominent hood or collar."	Thelymitra
52	"Lateral sepals much longer and narrower than dorsal sepal; leaves linear, basal."	53
52	"Lateral sepals similar in length and breadth to dorsal sepal; leaves mostly not linear, basal or cauline."	54
53	"Lateral petals oblong and concealed under dorsal sepal."	Orthoceras
53	"Lateral petals consisting of a prominent claw ending in a rounded to ovate lamina, exposed."	Diuris
54	"Sepals and lateral petals usually bright pink or rarely white, 4–5 mm long; column about as long as labellum; inflorescence many-flowered with flowers arranged in a spiral."	Spiranthes
54	"Sepals and lateral petals green or brown to reddish, sometimes striped with white, usually more than 5 mm long; column at least half as long as labellum; inflorescence 1–18-flowered, flowers not arranged in a conspicuous spiral."	55
55	"Dorsal sepal and lateral petals adherent, forming a hood; lateral sepals basally fused; labellum usually irritable."	Pterostylis
55	"Sepals and petals free; labellum not irritable."	56
56	"Inflorescence 6–18-flowered; leaves several, basal or cauline or both; labellum calli obscure or absent."	Rimacola
56	"Inflorescence 1-flowered; leaves 2, basal; labellum calli conspicuous"	Chiloglottis