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FOC | Family List | FOC Vol. 25

1. Orchidaceae

兰科 lan ke

Authors: Xinqi Chen, Zhongjian Liu, Guanghua Zhu, Kai-yung Lang, Zhanhe Ji, Yi-Bo Luo, Xiaohua Jin, Phillip J. Cribb, Jeffrey J. Wood, Stephan W. Gale, Paul Ormerod, Jaap J. Vermeulen, Howard P. Wood, Dudley Clayton & Alexandra Bell

Hemipilia flabellata

Credit: Harvard University Herbaria

Perennial, but sometimes short-lived, terrestrial, epiphytic, or lithophytic, autotrophic or rarely mycotrophic herbs (or rarely scrambling vines), with rhizomes, tubers, or rootstocks with mycorrhizal fungi in roots. Stems either sympodial or monopodial, usually leafy, but leaves sometimes reduced to bractlike scales, 1 or more internodes at base often swollen to form a "pseudobulb"; epiphytic species with aerial, photosynthesizing adventitious roots, often bearing 1 or more layers of dead cells (velamen). Leaves 1 to many, alternate or occasionally opposite, often distichous, sometimes terete or canaliculate, glabrous or very rarely hairy, frequently fleshy or leathery, base almost always sheathing, sometimes articulated, sometimes forming a false petiole, margin entire, apex often emarginate. Inflorescence basal, lateral, or terminal, erect to pendulous, racemose, spicate, subumbellate, or paniculate, 1- to many flowered, flowers rarely secund or distichously arranged. Flowers small to large, often quite showy, usually zygomorphic, very rarely ± actinomorphic, bisexual [very rarely monoecious and polymorphic], sessile or pedicellate, most often resupinate with pedicel and ovary twisted through 180°, occasionally not twisted or twisted through 360°. Ovary inferior, 1-locular, placentation parietal (or rarely 3-locular and placentation axile). Sepals usually free but sometimes variously adnate, median (dorsal) one often dissimilar to laterals, laterals sometimes adnate to a column foot to form a saccate, conic, or spurlike mentum. Petals free or rarely partly adnate to sepals, similar to sepals or not, often showy; lip entire, variously lobed or 2- or 3-partite, ornamented or not with calli, ridges, hair cushions, or crests, with or without a basal spur or nectary, margins entire to laciniate. Column short to long, with or without a basal foot, occasionally winged or with lobes or arms at apex or ventrally; anther mostly 1, less often 2 or 3, terminal or ventral on column, caplike or opening by longitudinal slits; pollen usually forming distinct pollinia, less often loose, pollinia 2, 4, 6, or 8, mealy, waxy, or horny, sectile or not, sessile or attached by stalks (caudicles or stipes) to 1 or 2 sticky viscidia; stigma 3-lobed, mid-lobe often modified to form a rostellum, other lobes either sunken on ventral surface of column behind anther or with 2 lobes porrect. Fruit a capsule, rarely berrylike, usually opening laterally by 3 or 6 slits. Seeds very numerous, dustlike, lacking endosperm, rarely winged.

About 800 genera and ca. 25,000 species (some estimates as high as 30,000 species): worldwide, except for Antarctica, most numerous in the humid tropics and subtropics; 194 genera (11 endemic, one introduced) and 1,388 species (491 endemic, one introduced) in five subfamilies in China.

Recent analyses of orchids incorporating data from DNA analyses have confirmed many aspects of the established classifications but have also provided some surprises for orchid taxonomists. First of all, the results have upheld the monophyly (evolutionary integrity, i.e., the group includes all the taxa derived from an ancestral species) of the orchid family, including the apostasioids and cypripedioids. They also suggest strongly that the orchids are an ancient group that evolved in the great southern continent of Gondwanaland before it split up to form the southern continents of Australia, Africa, and South America, the island of Madagascar, and the subcontinent of India. The subfamilies Apostasioideae, Cypripedioideae, and Orchidoideae (sensu Dressler, Phylogeny Classific. Orchid Fam. 1993) are all monophyletic. However, recent work clearly shows that Vanilla and its relatives form a separate and ancient clade (an evolutionary lineage including all the taxa derived from a single ancestral one) that deserves recognition as the subfamily Vanilloideae, that the Spiranthoideae nest within a more broadly defined Orchidoideae, and that Vandoideae are a specialized clade within a more broadly defined Epidendroideae.

A detailed new classification of the orchid family is currently being produced under the title Genera Orchidacearum, of which four of the six volumes have been published and a fifth is near completion (Pridgeon et al., Gen. Orchid. 1-4(1). 1999-2005). Even when this work is completed, such is the speed with which new information and techniques are being developed and published, it will almost certainly require revision. However, we now have the broad bones of a more robust and predictive classification of the family that will be more satisfactory than the presently widely used systems that are based mainly upon morphological characters.

The classification of the family is currently the subject of some debate, particularly the circumscription and the placement of certain tribes, subtribes, and genera. The classification of Chase et al. (in Dixon et al., Orchid Conservation, 69-89. 2003), elaborated in Pridgeon et al. (loc. cit.), which is strongly supported by recent molecular, embryological, and morphological analyses, is followed here. They recognize five subfamilies: Apostasioideae, Cypripedioideae, Vanilloideae, Orchidoideae, and Epidendroideae.

Lang Kaiyong, Chen Singchi, Luo Yibo & Zhu Guanghua. 1999. Orchidaceae (1). In: Lang Kaiyong, ed., Fl. Reipubl. Popularis Sin. 17: 1-499; Chen Singchi, Tsi Zhanhuo, Lang Kaiyong & Zhu Guanghua. 1999. Orchidaceae (2). In: Chen Singchi, ed., Fl. Reipubl. Popularis Sin. 18: 1-412; Tsi Zhanhuo, Chen Singchi, Luo Yibo & Zhu Guanghua. 1999. Orchidaceae (3). In: Tsi Zhanhuo, ed., Fl. Reipubl. Popularis Sin. 19: 1-437.

Key 3: Subfams. Orchidoideae, some Vanilloideae, primitive Epidendroideae

1 Plants with conspicuous, long, climbing stems; fruit a pod or a long capsule; seeds with thick testa, wingless or surrounded by ± annular wing.   51 Vanilla (p. 167)
+ Plants not climbing, stems erect; fruit a capsule; seeds without thick testa, with narrow, long wings at both ends, ± fusiform   (2)
2 (1) Plants leafless at anthesis   (3)
+ Plants with a leaf or leaves at anthesis   (4)
3 (2) Leaves many, often 7 or 8, oblong to elliptic, shortly petiolate; ovary and sepals pubescent.   21 Pelexia (p. 86)
+ Leaf 1, broadly ovate to cordate, long petiolate; ovary and sepals glabrous.   66 Nervilia (p. 197)
4 (2) Leaves plicate, papery or thinly leathery   (5)
+ Leaves not plicate, herbaceous or membranous   (10)
5 (4) Leaves clustered on lower part to base of stem; pollinia 8, in 2 groups.   73 Bletilla (p. 209)
+ Leaves spaced above middle of stem, or rarely clustered at its apex; pollinia 2 or 4   (6)
6 (5) Inflorescence lateral or terminal; flowers densely arranged on a shortened inflorescence; rostellum long and erect; pollinarium with sectile pollinia, with caudicle and viscidium   (7)
+ Inflorescence terminal; flowers scattered on a long inflorescence; rostellum very small or nearly absent; pollinarium with granular pollinia, without caudicle and viscidium   (8)
7 (6) Inflorescence unbranched; sepals less than 1 cm; basal part of lip wider than its apical part.   64 Tropidia (p. 195)
+ Inflorescence branched; sepals more than 3 cm; apical part of lip wider than its basal part.   65 Corymborkis (p. 197)
8 (6) Flowers actinomorphic, with lip similar to petals; stigma terminal.   58 Tangtsinia (p. 177)
+ Flowers zygomorphic, with lip conspicuously different from petals; stigma lateral   (9)
9 (8) Flowers concolorous, white or yellow; upper bracts small, not foliaceous, shorter than pedicel and ovary (except C. damasonium); lip 3-lobed, saccate or spurred at base.   57 Cephalanthera (p. 174)
+ Flowers usually not concolorous, green, brown, purple, or yellow; upper bracts large, foliaceous, longer than pedicel and ovary; lip contracted in middle forming epichile and hypochile, neither spurred nor saccate at base, sometimes with concave hypochile.   60 Epipactis (p. 179)
10 (4) Leaves 2, inserted at or near middle of stem, opposite or subopposite.   63 Neottia (p. 184)
+ Leaves 1 or more than 2, or if 2, then either adpressed to ground or clearly alternate   (11)
11 (10) Pollinia granular, without separable massulae   (12)
+ Pollinia sectile, with many separable massulae   (17)
12 (11) Leaves many, basal.   20 Spiranthes (p. 84)
+ Leaves 1 or 2, basal or cauline   (13)
13 (12) Leaves basal; flowers usually more than 10   (14)
+ Leaves cauline; flowers 1 or 2(or 3)   (15)
14 (13) Leaves flat, 40-50 mm wide, with long, distinct petiole; plants with a few ± fleshy roots.   24 Cryptostylis (p. 88)
+ Leaves cylindric, 2-3 mm wide, without distinct petiole; plants with globose tubers.   25 Microtis (p. 89)
15 (13) Leaves elliptic to oblong-lanceolate, 3-8 cm, not reticulate-veined; plants without tubers.   56 Pogonia (p. 172)
+ Leaves ovate to cordate, less than 2 cm, reticulate-veined; plants with globose tubers   (16)
16 (15) Bracts not leaflike; lip with 2 spurs.   22 Corybas (p. 86)
+ Bracts leaflike; lip without any spur.   23 Stigmatodactylus (p. 88)
17 (11) Anther connected to column by a narrow base, never completely connate to column, often narrowed and elongated toward apex, wholly withered or deciduous later; caudicle protruding from anther apex   (18)
+ Anther connate to column with its broad base or back, not narrowed toward apex, persistent; caudicle protruding from base of anther   (32)
18 (17) Stigma 1   (19)
+ Stigmas 2, lateral (except in Odontochilus tortus)   (23)
19 (18) Lip separate from column, not divided into apical and basal parts, wholly cymbiform or pouchlike or basal half concave-saccate; sac or pouch not 2-lobed at apex   (20)
+ Lip ± adnate to column at base, divided into apical and basal parts, base with a sac or spur shallowly 2-lobed at apex   (21)
20 (19) Lip cymbiform or basal half concave-saccate; pollinia subsessile.   5 Goodyera (p. 45)
+ Lip pouchlike; pollinia with a long caudicle.   6 Hylophila (p. 54)
21 (19) Column twisted; rostellum not forked to 2-lobed; lip saccate at base.   7 Ludisia (p. 55)
+ Column straight; rostellum forked to 2-lobed; lip spurred at base   (22)
22 (21) Spur 7-10 mm; lip with 1 lamella and 2 calli on disk.   8 Herpysma (p. 56)
+ Spur 1.5-4 mm; lip without lamella or callus on disk.   9 Erythrodes (p. 56)
23 (18) Sepals ± connate into a tube   (24)
+ Sepals free   (25)
24 (23) Sepals connate at or above middle forming a tube; column with 2 erect, armlike appendages.   10 Cheirostylis (p. 57)
+ Sepals connate below middle forming a tube; column without armlike appendages.   11 Kuhlhasseltia (p. 63)
25 (23) Leaves 4-15 mm; inflorescence with 1 or 2(or 3) flowers.   12 Myrmechis (p. 63)
+ Leaves more than 20 mm; inflorescence usually with 3 to many flowers   (26)
26 (25) Flowers not resupinate, with lip at top, usually without a mesochile (mesochile present with involute margins in H. anomala).   13 Hetaeria (p. 65)
+ Flowers resupinate, with lip at bottom (except a few species in Anoectochilus in which lip has a fimbriate or fimbriate-toothed mesochile)   (27)
27 (26) Lip with a cylindric or fusiform spur   (28)
+ Lip lacking a spur   (29)
28 (27) Column lacking ventral wings; lip without a mesochile; lip hypochile containing 2 stalked glands.   17 Vrydagzynea (p. 76)
+ Column with ventral wings; lip with an often toothed or pectinate mesochile; lip hypochile without stalked glands inside.   18 Anoectochilus (p. 76)
29 (27) Lip with a raised median keel.   14 Rhomboda (p. 67)
+ Lip lacking a raised median keel   (30)
30 (29) Stigma lobes stalked; lip with an elongate, involute mesochile; inflorescence 1- or 2-flowered.   12 Myrmechis (p. 63)
+ Stigma lobes not stalked; inflorescence several flowered   (31)
31 (30) Lip with an elongate mesochile with entire to lacerate flanges; column twisted; stigma lobes apical.   19 Odontochilus (p. 80)
+ Lip with a short mesochile, rarely with entire flanges; column not twisted; stigma lobes lateral.   16 Zeuxine (p. 71)
32 (17) Lip uppermost, hooded, with 2 spurs.   50 Satyrium (p. 165)
+ Lip usually lowermost, not hooded, with 1 or no spur   (33)
33 (32) Lateral sepals ± saccate or ± spurlike near middle; anther not erect due to recurved column; lip erect, not spurred; leaves less than 2 cm.   49 Disperis (p. 164)
+ Lateral sepals never saccate or spurlike near middle; anther erect; lip spreading or nodding, base often spurred; leaves often more than 2 cm   (34)
34 (33) Lip with 2 pores toward base.   48 Porolabium (p. 164)
+ Lip lacking pores   (35)
35 (34) Connective broadly hooded; 2 anther locules widely separated.   47 Androcorys (p. 162)
+ Connective not hooded; 2 anther locules close together   (36)
36 (35) Stigma often 1 (rarely 2 in some Platanthera species)   (37)
+ Stigmas 2, usually separate, conjoined in Bhutanthera   (47)
37 (36) Viscidia hidden in a common bursicle   (38)
+ Viscidia naked or hidden in 2 separate bursicles   (39)
38 (37) Rootstock of tubers, subglobose, ovoid, or ellipsoid, not divided.   26 Orchis (p. 90)
+ Rootstock a creeping rhizome.   27 Galearis (p. 90)
39 (37) Stigma raised and thickened   (40)
+ Stigma often neither raised nor thickened (except some Platanthera species with (1 or)2 stigmas)   (43)
40 (39) Staminode with a stalk; rostellum absent; sepals and petals ± connivent into a hood.   34 Diphylax (p. 117)
+ Staminode sessile; rostellum small but distinct; sepals not connivent   (41)
41 (40) Rostellum similar in appearance to stigma; flowers 2-3 mm wide, not resupinate, with lip at top.   33 Smithorchis (p. 117)
+ Rostellum different in appearance from stigma; flowers 7-8 mm wide, resupinate, with lip at bottom   (42)
42 (41) Flowers usually pink or purple, often spotted purple on lip, or green with a chestnut-brown lip; plants with palmate tubers; viscidia naked; lip without 2 small lobes at base.   32 Dactylorhiza (p. 114)
+ Flowers white, cream-colored, yellow-green, or green; plants with fusiform tubers; viscidia enclosed in shell-like bursicles formed by rostellum margins; lip with 2 very small lobes at base.   31 Platanthera (p. 101)
43 (39) Tubers digitately or palmately lobed.   32 Dactylorhiza (p. 114)
+ Tubers ovoid, ellipsoidal, or fusiform   (44)
44 (43) Bracts leafy, leaves merging into floral bracts.   30 Brachycorythis (p. 100)
+ Bracts distinctly smaller than leaves and not leaflike   (45)
45 (44) Lip ligulate; flowers white, yellow-green, or green.   31 Platanthera (p. 101)
+ Lip lobed, not ligulate; flowers often purple or pink   (46)
46 (45) Anther locules parallel, connective obscure; lip lacking calli at mouth of spur.   28 Ponerorchis (p. 92)
+ Anther locules divergent, with a broad connective; lip with 2 small calli at mouth of spur.   29 Hemipilia (p. 98)
47 (36) Tubers fusiform or tapering to a slender apex, sometimes digitately or palmately divided   (48)
+ Tubers ovoid, ellipsoid, or somewhat cylindric   (49)
48 (47) Tubers palmately or digitately divided; flowers pink to purple; lip 3-lobed, often obscurely so.   38 Gymnadenia (p. 133)
+ Tubers fusiform, not divided; flowers white, green, or yellow-green; lip ligulate.   31 Platanthera (p. 101)
49 (47) Viscidia involute and hornlike; lip often spurless.   35 Herminium (p. 119)
+ Viscidia not involute, sometimes slightly curved, but not hornlike; lip often spurred   (50)
50 (49) Rostellum without distinct arms, beaklike or square to triangular   (51)
+ Rostellum with arms, neither beaklike nor square to triangular   (53)
51 (50) Rostellum beaklike, 1-toothed on either side; underground rhizomes cylindric; viscidium hidden in a cavity formed by lip and column.   39 Tsaiorchis (p. 135)
+ Rostellum square or triangular, toothless; underground tubers ellipsoid or palmate; viscidium naked   (52)
52 (51) Raceme not secund; sepals completely separate from each other; leaf often 1.   36 Amitostigma (p. 124)
+ Raceme often secund; sepals connate for ca. 3/4 into a hood; leaves often 2-4 or more.   37 Neottianthe (p. 131)
53 (50) Viscidium hidden within a tubular fold at end of rostellum arm.   40 Pecteilis (p. 136)
+ Viscidium naked   (54)
54 (53) Rostellum arms very short; anther with 2 parallel locules; flowers small.   41 Peristylus (p. 137)
+ Rostellum arms long; anther with 2 usually divergent locules   (55)
55 (54) Stem, rachis, leaves, and ovary all spotted with purple; spur with a large mouth and globose apex.   43 Hemipiliopsis (p. 160)
+ Stem, rachis, leaves, and ovary not all spotted with purple; spur without a swollen globose apex and large mouth   (56)
56 (55) Inflorescence with 1(or 2) rather large flowers; petals 10-21 mm, much longer than sepals.   46 Diplomeris (p. 162)
+ Inflorescence with 1 or 2 very small flowers (4-5 mm in diam.) or 3 to many rather large flowers; petals smaller than sepals   (57)
57 (56) Inflorescence with 1 or 2 flowers; stigmas conjoined, pulvinate; tubers ovoid or globose.   44 Bhutanthera (p. 161)
+ Inflorescence usually with 3 to many flowers; stigmas separate, not pulvinate; tubers ellipsoid or oblong or gourd-shaped   (58)
58 (57) Seed fusiform with elongated testa cells, lacking any appendages; plants 8-75 cm tall; tubers ellipsoid or oblong.   42 Habenaria (p. 144)
+ Seed lacking elongated testa and with a baglike appendage on each side; plants 3-4 cm tall; tubers gourd-shaped.   45 Frigidorchis (p. 161)

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