previous arrow
next arrow


Annual or perennial, terrestrial, epiphytic, or lithophytic herbs (or rarely vines), with rhizomes, tubers, rootstocks or aerial roots. Stems sympodial or monopodial, usually leafy, sometimes modified to scales or pseudobulb. Leaves 1 to many, alternate or opposite, distichous, sometimes terete or canaliculate, fleshy or leathery, base sheathing, sometimes articulated, or forming a false petiole, margin entire, apex emarginate. Inflorescence basal, lateral, or terminal, erect to pendulous, racemose, spicate, subumbellate, or paniculate. Flowers usually showy, zygomorphic, rarely actinomorphic, bisexual. Sepals free or variously adnate, median (dorsal) one often dissimilar to laterals. Petals free or partly adnate to sepals; lip entire, variously lobed, with or without a basal spur. Column with or without a basal foot; anther mostly 1, rarely 2 or 3, caplike or opening by longitudinal slits; pollen forming distinct pollinia, rarely loose, pollinia 2, 4, 6, or 8, mealy, waxy, or horny, sectile, sessile or attached by stalks called caudicles to 1 or 2 sticky viscidia; stigma 3-lobed, mid-lobe often modified to form a rostellum, other lobes either sunken or with 2 lobes porrect. Ovary inferior, 1-locular, placentation parietal. Fruit a capsule, rarely berry, opening laterally by 3 or 6 slits. Seeds numerous, dustlike, lacking endosperm, rarely winged.

Key to the Genus

Serial Key Reference
1a. Fertile stamens 2, opposite to lateral petals; pollen not forming pollinia Apostasia
1b. Fertile stamen 1, rarely 2, if 2, opposite to dorsal sepal and lip; pollen forming pollinia 2
2a. Holomycotrophic plants 3
2b. Autotrophic plants 4
3a. Lip not saccate or spurred at base; column foot absent Cymbidium
3b. Lip saccate or spurred at base; column foot conspicuous Eulophia
4a. Plants always terrestrial; leaves not articulated; pollinia soft or sectile 5
4b. Plants mostly epiphytic, rarely terrestrial; leaves often articulated at base; pollinia waxy or bony, hard or relatively hard 14
5a. Plants with long climbing stems; seeds wingless, with thick testa Vanilla
5b. Plants not climbing, stems erect; seeds winged, without thick testa 6
6a. Plants leafless at anthesis Nervilia
6b. Plants with a leaf or leaves at anthesis 7
7a. Leaves plicate, papery or thinly leathery 8
7b. Leaves not plicate, herbaceous or membranous 9
8a. Inflorescence unbranched; sepals less than 1 cm Tropidia
8b. Inflorescence branched; sepals more than 3 cm Corymborkis
9a. Pollinia granular, without separable massulae Spiranthes
9b. Pollinia sectile, with many separable massulae 10
10a. Anther connected to column by a narrow base, deciduous later; caudicle protruding from anther apex 11
10b. Anther connected to column with its broad base or back, persistent; caudicle protruding from base of anther 13
11a. Stigma 1 Goodyera
11b. Stigmas 2 12
12a. Flowers not resupinate, with lip at top Hetaeria
12b. Flowers resupinate, with lip at bottom Zeuxine
13a. Stigma 1 Brachycorythis
13b. Stigmas 2 Peristylus
14a. Plants monopodial, without pseudobulbs or thickened stems, rhizomes, or tubers; pollinia bony, very hard, with a common stipe 15
14b. Plants sympodial, mostly with pseudobulbs or thickened stems, rhizomes, or tubers; pollinia not very hard, usually without stipe 36
15a. Pollinia 4, subglobose, separate from each other Micropera
15b. Pollinia 2, sometimes each divided into 2 pieces, but then not subglobose 16
16a. Each pollinium porate at apex 17
16b. Each pollinium cleft or split into 2 unequal halves 18
17a. Lip neither spurred nor saccate Luisia
17b. Lip spurred or saccate at base Gastrochilus
18a. Each pollinium cleft or split 19
18b. Each pollinium completely divided into 2 unequal halves 27
19a. Column foot conspicuous 20
19b. Column foot absent or very inconspicuous 23
20a. Leaves terete Papilionanthe
20b. Leaves flat 21
21a. Lip spurless Phalaenopsis
21b. Lip spurred 22
22a. Lip spur often horn-shaped, curved Aerides
22b. Lip spur usually oblong-cylindric, not curved Pteroceras
23a. Stipe broad, shorter or slightly longer than pollinia Vanda
23b. Stipe narrow, much longer than pollinia 24
24a. Plants with thick aerial roots; leaves 20-40 cm long Rhynchostylis
24b. Plants without thick aerial roots; leaves 4-20 cm long 25
25a. Stipe linear, apex curving forward, sigmoid, rising behind and above pollinia, pollinia separated by a vertical lamella on stipe. Uncifera
25b. Stipe not as above 26
26a. Plants rather long stemmed, with distant leaves; spur of lip contracted in middle and then globose and circinate at apex, ornamented inside. Robiquetia
26b. Plants very short stemmed (1-6 cm); spur of lip not as above, unornamented inside Saccolabiopsis
27a. Column foot conspicuous 28
27b. Column foot inconspicuous or absent 29
28a. Stem 2-8 cm long, with (4-)6-10 or more cauline leaves; lip without any appendage between 2 lateral lobes Thrixspermum
28b. Stem often less than 1 cm long, with 3-5 subbasal leaves; lip with 1 fleshy or forked appendage between 2 lateral lobes Phalaenopsis
29a. Lip with neither spur nor sac at base Diploprora
29b. Lip with a spur or sac at base 30
30a. Spur of lip with a longitudinal (various in length) septum or ridge inside 31
30b. Spur of lip without septum or ridge inside 33
31a. Inflorescence ca. 1 cm long, with 2-7 flowers; column with 2 linear and curved appendages Pelatantheria
31b. Inflorescence more than 3 cm, usually with more than 10 flowers; column without appendages 32
32a. Pollinia 4 Cleisostoma
32b. Pollinia 2 Cleisomeria
33a. Spur with appendage (often ligulate) on inner wall 34
33b. Spur usually without appendage on inner wall 35
34a. Spur with an erect, forked-tipped tongue in middle or near bottom of back wall; column not conspicuously toothed, glabrous. Pomatocalpa
34b. Spur with a movable, hairy tongue in upper part of back wall; column toothed, hairy Staurochilus
35a. Flowers not resupinate, with lip at top Acampe
35b. Flowers resupinate, with lip at bottom Smitinandia
36a. Pollinia 2 37
36b. Pollinia 4-8 40
37a. Leaves with neither long petiole nor pseudostem; lip not saccate or spurred at base; 38
37b. Leaves long petiolate; petioles often forming a pseudostem; lip saccate or spurred at base; 39
38a. Leaves several to many, distichous; lip not forming a tube with column foot Cymbidium
38b. Leaf solitary; lip forming a tube with column foot Thecostele
39a. Inflorescence erect; anther cap with 2 projections Eulophia
39b. Inflorescence nodding; anther cap without projections Geodorum
40a. Pollinia 8 41
40b. Pollinia 4-6
41a. Inflorescence globose head, densely flowered; sepals 4-5 mm Agrostophyllum
41b. Inflorescence racemose or reduced to a single flower; sepals (8-)10-70 mm 42
42a. Column without a conspicuous foot 43
42b. Column with a conspicuous foot 46
43a. Pseudobulbs subglobose to ovoid-globose, with 1-5 terminal leaves; viscidium triangular. Spathoglottis
43b. Pseudobulbs cylindric to conic, sometimes absent or replaced by long stems, with several to many basal or lateral leaves; viscidium absent or if present then not triangular 44
44a. Stem terete, with more than 10 leaves along lower to upper part Arundina
44b. Stem, if present, with 2-6(-8) leaves above middle 45
45a. Stigma usually subterminal; lip neither spurred nor saccate at base, vesiculate on mid-lobe or disk. Cephalantheropsis
45b. Stigma lateral; lip often spurred or saccate, very rarely spurless, not vesiculate on mid-lobe or disk Spathoglottis
46a. Scape or inflorescence arising from upper part to apex of stem or pseudobulbs 47
46b. Scape or inflorescence arising from middle to base of pseudobulbs or from rhizome 48
47a. Stem with 1 distinct internode only Eria
47b. Stem usually with several internodes Pinalia
48a. Plants leafless at anthesis, with neither pseudobulb nor conspicuous stem; rhizome fleshy, usually geniculate. Pachystoma
48b. Plants with leaves at anthesis 49
49a. Leaf 1, petiolate; petiole similar to pseudobulb Tainia
49b. Leaves 2 to many, petiolate; petiole quite different from pseudobulb, sometimes overlapping to form a pseudostem 50
50a. Column with a conspicuous foot; mentum clearly visible 51
50b. Column without a conspicuous foot; mentum absent 52
51a. Inflorescence arising from base of pseudobulbs or from rhizome Bulbophyllum
51b. Inflorescence arising from upper part of stem or pseudobulbs Dendrobium
52a. Leaves laterally compressed or sometimes cylindric. Oberonia
52b. Leaves flat, not as above 53
53a. Terrestrial plants, without green naked pseudobulbs 54
53b. Epiphytic plants, with green naked pseudobulbs 56
54a. Column rather long, arching; flowers resupinate. Liparis
54b. Column often very short, erect; flowers often not resupinate, with lip at top; always terrestrial 55
55a. Leaf 1 or 2, lacking prominent veins Malaxis
55b. Leaves 2 or more, with prominent veins Crepidium
56a. Lip concave-saccate at base Pholidota
56b. Lip not or slightly concave, but never saccate at base Coelogyne