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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 4: Subfam. Epidendroideae: monopodial taxa

1 Plants with leaves reduced to inconspicuous scarious scales, roots containing chlorophyll, often ± flattened against substrate   (2)
+ Plants with normal green leaves   (3)
2 (1) Scape or inflorescence erect, less than 2 cm, glabrous.   145 Taeniophyllum (p. 444)
+ Scape or inflorescence pendulous, more than 10 cm, densely hairy.   169 Chiloschista (p. 470)
3 (1) Pollinia 4, subglobose, separate from each other   (4)
+ Pollinia 2, sometimes each divided into 2 pieces, but then not subglobose   (7)
4 (3) Terrestrial plants; lip 5-lobed; column foot to 6 mm.   148 Doritis (p. 445)
+ Epiphytic plants; lip ± 3-lobed; column foot absent or very short   (5)
5 (4) Stem very short, invisible; leaves all basal; lip with a sac at base of mid-lobe.   149 Nothodoritis (p. 446)
+ Stem elongate, 25-100 cm; leaves cauline; lip with a spur at base   (6)
6 (5) Inflorescence axillary; leaf blade linear, 1.5-1.8 cm wide.   146 Sarcophyton (p. 445)
+ Inflorescence often leaf-opposed; leaf blade lorate, 3-4.5 cm wide.   147 Micropera (p. 445)
7 (3) Pollinia subglobose, not cleft, split, or porate   (8)
+ Pollinia ± cleft, split, or porate, sometimes each completely divided into 2 pieces   (13)
8 (7) Plants very small; leaves 0.5-1.5 cm; sepals and petals connate at base to form a tube.   189 Microtatorchis (p. 503)
+ Plants small to medium-sized; leaves 4-17 cm; sepals and petals free   (9)
9 (8) Column with a conspicuous foot   (10)
+ Column without a foot   (11)
10 (9) Scape glabrous; stem 2-12 cm.   192 Parapteroceras (p. 505)
+ Scape densely minutely hispid; stem less than 1 cm.   190 Grosourdya (p. 504)
11 (9) Lateral lobes of lip large, apical margin serrate or fimbriate.   193 Pennilabium (p. 505)
+ Lateral lobes of lip inconspicuous, margin neither serrate nor fimbriate   (12)
12 (11) Rachis slender, never thickened and sulcate, never clavate; column hammer-shaped; stipe linear-spatulate, much broadened at apex.   194 Malleola (p. 506)
+ Rachis fleshy, sulcate, or sometimes clavate, few to many flowered, with a few or all flowers open simultaneously; column short and stout, not hammer-shaped; stipe linear, not broadened at apex.   191 Tuberolabium (p. 504)
13 (7) Each pollinium porate at apex   (14)
+ Each pollinium cleft or split, or sometimes divided into 2 unequal halves   (20)
14 (13) Lip neither spurred nor saccate   (15)
+ Lip spurred or saccate at base   (17)
15 (14) Leaves narrowly terete.   183 Luisia (p. 488)
+ Leaves not terete   (16)
16 (15) Inflorescence 0.5-1.5 cm; lip 3-lobed; column foot short but distinct.   182 Biermannia (p. 487)
+ Inflorescence 2-4 cm; lip contracted in middle; column foot absent.   184 Haraella (p. 491)
17 (14) Lip not 3-lobed, often contracted in middle and with a pouchlike or saccate hypochile, lacking lateral lobes.   185 Gastrochilus (p. 491)
+ Lip 3-lobed, base with a distinct spur and 2 lateral lobes on both sides of its mouth   (18)
18 (17) Lateral sepals wider than dorsal sepal, oblique; spur tapered toward apex; mid-lobe of lip 7-15 mm wide; pedicel and ovary 1.7-5 cm.   186 Holcoglossum (p. 499)
+ Lateral sepals similar to dorsal sepal; spur cylindric, usually ± dilated toward apex; mid-lobe of lip 1-4 mm wide; pedicel and ovary 0.6-1.5 cm   (19)
19 (18) Lateral lobes of lip inserted beside entrance of spur; lip often with appendages at base; spur 5-15 mm; sepals and petals 4-9 × 2-6 mm.   187 Ascocentrum (p. 502)
+ Lateral lobes of lip inserted distally to spur on sides of mid-lobe; spur 2-2.3 mm; sepals and petals 2.5-3.5 × 1.2-1.7 mm.   188 Penkimia (p. 503)
20 (13) Each pollinium cleft or split   (21)
+ Each pollinium completely divided into 2 unequal halves, halves never globose   (32)
21 (20) Column foot conspicuous   (22)
+ Column foot absent or very inconspicuous   (26)
22 (21) Leaves terete.   175 Papilionanthe (p. 477)
+ Leaves flat   (23)
23 (22) Lip spurless   (24)
+ Lip spurred, spur spreading at a right angle to column foot   (25)
24 (23) Lip immovable.   176 Phalaenopsis (p. 478)
+ Lip movable.   177 Chamaeanthus (p. 483)
25 (23) Lip spur often horn-shaped, curved; mid-lobe large, flat.   180 Aerides (p. 485)
+ Lip spur usually oblong-cylindric, not curved; mid-lobe fleshy, strongly reduced.   181 Pteroceras (p. 486)
26 (21) Lip movable.   179 Sedirea (p. 484)
+ Lip immovable   (27)
27 (26) Stipe broad, short, shorter or slightly longer than pollinia; viscidium usually suborbicular to transversely elliptic.   170 Vanda (p. 471)
+ Stipe narrow, long, much longer than pollinia, usually widened toward apex; viscidium not as above   (28)
28 (27) Plants large, with thick aerial roots; leaves 20-40 cm.   171 Rhynchostylis (p. 474)
+ Plants medium-sized, without thick aerial roots; leaves 4-20 cm   (29)
29 (28) Stipe linear, apex curving forward, sigmoid, rising behind and above pollinia, pollinia separated by a vertical lamella on stipe.   172 Uncifera (p. 475)
+ Stipe not as above   (30)
30 (29) Plants rather long stemmed, with distant leaves; spur of lip contracted in middle and then globose and circinate at apex, ornamented inside.   173 Robiquetia (p. 475)
+ Plants very short stemmed (1-6 cm); spur of lip not as above, unornamented inside   (31)
31 (30) Flowers minute (sepals 2-2.5 mm); inflorescence slender, laxly many flowered; mid-lobe of lip (when present) tiny, spur short, often saccate, not slender or slightly curved.   174 Saccolabiopsis (p. 476)
+ Flowers larger (sepals 8-10 mm); inflorescence few flowered; mid-lobe of lip large, spreading horizontally, spur slender, cylindric, sometimes slightly curved.   178 Neofinetia (p. 483)
32 (20) Column foot conspicuous   (33)
+ Column foot inconspicuous or absent   (34)
33 (32) Stem often elongate, 2-8 cm, with (4-)6-10 or more cauline leaves (except T. eximium); lip without any appendage between 2 lateral lobes or at base of mid-lobe adaxially.   168 Thrixspermum (p. 466)
+ Stem short, often less than 1 cm, with 3-5 subbasal leaves; lip with 1 fleshy or forked appendage between 2 lateral lobes or at base of mid-lobe adaxially.   176 Phalaenopsis (p. 478)
34 (32) Lip movable   (35)
+ Lip immovable   (37)
35 (34) Both sepals and petals oblanceolate or narrowly spatulate, 5-6 × as long as wide.   167 Arachnis (p. 465)
+ Both sepals and petals broadly obovate to obovate-elliptic, 2-3 × as long as wide   (36)
36 (35) Stem 10-20 cm, with 3-5 leaves; sepals and petals marked with colored spots; viscidium small, suborbicular.   166 Hygrochilus (p. 465)
+ Stem 20-70 cm, often with 6-8 leaves; sepals and petals marked with colored transverse stripes; viscidium large, saddlelike.   165 Esmeralda (p. 464)
37 (34) Lip with neither spur nor sac at base, sometimes concave   (38)
+ Lip with a spur or sac at base   (39)
38 (37) Inflorescence 30-50 cm, much longer than leaves; flowers 5-6 cm in diam.; lip shorter than either sepals or petals.   150 Vandopsis (p. 446)
+ Inflorescence 10-15 cm, shorter or slightly longer than leaves; flowers 1.5-2 cm in diam.; lip longer than either sepals or petals.   151 Diploprora (p. 447)
39 (37) Spur of lip with a longitudinal (various in length) septum or ridge inside   (40)
+ Spur of lip without septum or ridge inside   (43)
40 (39) Inflorescence ca. 1 cm, with 2-7 flowers; column with 2 linear and curved appendages on both sides toward apex.   161 Pelatantheria (p. 456)
+ Inflorescence more than 3 cm, usually with more than 10 flowers; column without appendages as above   (41)
41 (40) Rostellum very small; pollinia without caudicles; stipe various in shape but not long linear or curved.   163 Cleisostoma (p. 458)
+ Rostellum large; pollinia with short but distinct caudicles; stipe long linear, ± curved   (42)
42 (41) Leaves unequally and deeply bilobed at apex; stipe strongly curved.   162 Sarcoglyphis (p. 457)
+ Leaves very minutely bilobed at apex; stipe slightly curved.   164 Stereochilus (p. 463)
43 (39) Spur with appendage (often ligulate) on inner wall   (44)
+ Spur usually without appendage on inner wall   (47)
44 (43) Leaves terete; spur with Y-shaped appendage on back wall.   157 Cleisostomopsis (p. 453)
+ Leaves not terete; spur with tongue-shaped appendage on back wall   (45)
45 (44) Spur with an erect, forked-tipped tongue in middle or near bottom of back wall; column not conspicuously toothed, glabrous.   160 Pomatocalpa (p. 455)
+ Spur with a movable, hairy tongue in upper part of back wall; column toothed, hairy   (46)
46 (45) Inflorescence 0.5-1(-1.5) cm, much shorter than leaves, densely several flowered or reduced to a single flower.   158 Trichoglottis (p. 453)
+ Inflorescence 5-45 cm, nearly as long as or much longer than leaves, sparsely several to many flowered.   159 Staurochilus (p. 454)
47 (43) Flowers not resupinate, with lip at top.   153 Acampe (p. 449)
+ Flowers resupinate, with lip at bottom   (48)
48 (47) Lip clawed basally, with a spur in apical half of claw; spur far from ovary; mid-lobe erose-crisped or fimbriate along margins; column with a very short foot.   152 Ornithochilus (p. 448)
+ Lip not clawed at base, spurred at base; spur close to ovary; mid-lobe entire; column footless   (49)
49 (48) Flowers 3-5 cm in diam.; lip much smaller than petals, almost 1/10 as long as petals.   155 Renanthera (p. 451)
+ Flowers less than 1 cm in diam.; lip nearly as large as petals   (50)
50 (49) Lip with a fleshy transverse appendage at base of mid-lobe over entrance to spur.   154 Smitinandia (p. 450)
+ Lip without a fleshy transverse appendage over entrance to spur.   156 Schoenorchis (p. 452)

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