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139. Dendrobium Swartz, Nova Acta Regiae Soc. Sci. Upsal., ser. 2. 6: 82. 1799.
石斛属 shi hu shu
Authors: Guanghua Zhu, Zhanhe Ji, Jeffrey J. Wood & Howard P. Wood
Herbs epiphytic, lithophytic, or less often terrestrial, polymorphic, deciduous or evergreen. Stems either: 1) rhizomatous, 2) erect and many noded, 3) erect and 1-noded or several noded from a many-noded rhizome, or 4) without a rhizome, new stems of many nodes arising from base of old ones; 1 or 2(-500) cm, tough or fleshy, 1 to several internodes swollen at or near base or along entire length to form canelike pseudobulbs, ± covered with sheathing leaf bases and cataphylls, often turning yellow when dried. Leaves 1 to many, alternate, apical or distichous along stem, linear, lanceolate, oblong, or ovate, sometimes subterete or terete, papery to rigid and leathery, sometimes with black or brown trichomes especially on sheath, base articulate and often with clasping sheaths, apex usually 2-lobed or emarginate. Inflorescences lateral, generally distal, in some sections pseudoterminal, 1- to many flowered, usually racemose, erect, horizontal, or pendulous; floral bracts usually insignificant. Flowers extremely variable in color and shape, often showy, very small to large, resupinate or not resupinate, usually spreading, ephemeral or long-lived. Sepals similar, free, short to filiform; lateral sepals adnate to elongated column foot and part of lip to form a mentum, 0.1-3 cm. Petals free, margin entire to fimbriate; lip entire to distinctly 3-lobed, base joined to column foot, sometimes narrowly clawed at base, sometimes forming a closed spur with lateral sepals to which it may be joined laterally for a short distance; disk with 1 to several keels, sometimes verrucose-papillose, calli rarely present, sometimes with a transverse basal ridge. Column short, stout; foot long, sometimes with a protuberance adaxially; apical stelidia obscure to distinct; viscidium present; pollinia 4 in appressed pairs, waxy, ovate or oblong, naked, i.e., without caudicles or stipes.
About 1,100 species: India across to Japan, south to Malaysia and Indonesia, east to Australia, New Guinea, and the Pacific islands; 78 species (14 endemic) in 14 sections in China.
See the monograph by Seidenfaden (Opera Bot. 83: 1-295. 1985) and the book by H. P. Wood (Dendrobiums. 2006).
After publication of the treatment for the Flora of China, one species was newly recorded from China (see JIN Xiao-Hua et al. 2010.
Acta Bot. Yunnan. 32: 331-333, i.e., Dendrobium praecinctum Rchb. f.).
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Key 3
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| 1 |
Stem nodes and internodes swollen, at least on branches, sometimes moniliform |
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(2) |
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Stem nodes and internodes not swollen |
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(6) |
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| 2 (1) |
Stems slender, multi-branched, nodes and internodes swollen and moniliform; leaves less than 5 mm wide, distal on branches. |
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15 D. falconeri |
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Stems often stout, unbranched; leaves more than 5 mm wide |
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(3) |
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| 3 (2) |
Peduncle with sheaths 2-3 cm; flowers white, stained purplish red at apex; lip retuse, disk yellow with 2 dark purple spots. |
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16 D. wardianum |
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Peduncle at base with sheaths 3-6 cm; flowers not as above |
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(4) |
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| 4 (3) |
Floral bracts ovate, 5-6 mm; inflorescences subterminal from a leafy stem; flowers white with roseate tips; lip disk golden yellow below middle, with several purplish red stripes at base on either side; individual internodes swollen and obconic. |
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19 D. findlayanum |
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Floral bracts broadly ovate, 7-10 mm; inflorescences on leafless stems; flowers white with pale purple or purplish red tips |
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(5) |
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| 5 (4) |
Stem nodes ± swollen, but not moniliform; lip disk at center with a pale yellow lunate spot, both sides of base with several purplish red stripes. |
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17 D. gratiosissimum |
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Nodes and internodes swollen, moniliform; lip disk below middle with golden yellow spot, base without purplish red stripes. |
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18 D. pendulum |
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| 6 (1) |
Stem often narrow in lower part, wider distally; leaf apex unequally bilobed |
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(7) |
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Stem usually evenly cylindric, becoming narrower distally |
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(8) |
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| 7 (6) |
Lip broadly ovate, much larger than petals. |
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28 D. nobile |
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Lip broadly oblong, ca. as large as petals or smaller. |
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29 D. linawianum |
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| 8 (6) |
Sheaths on internodes with green and white stripes; flowers pale purplish red; lip suborbicular, pale purplish red above middle, golden yellow below middle. |
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26 D. crepidatum |
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Sheaths on internodes without green and white stripes |
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(9) |
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| 9 (8) |
Sepals and petals uniformly purple or purplish red |
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(10) |
| + |
Sepals and petals white, yellowish green, or pale yellow, sometimes tinged with purplish red at apex only |
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(11) |
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| 10 (9) |
Lip margin entire, only minutely hairy; sepals ca. 3.5 cm; lip blade broadly ovate, purplish red at edge, disk with 1 deep purple spot below middle surrounded by a white circle. |
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27 D. lituiflorum |
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Lip margin fimbriate-hairy; sepals ca. 2.7 cm; lip blade rhombic-orbicular, disk with deep purple spots on either side which coalesce. |
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20 D. parishii |
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| 11 (9) |
Stems clambering, limp, and pendulous, branching distally; flowers solitary, borne on a leafy stem (but leaves often variably deciduous); sepals and petals white or white tinged with pale purplish red; sepals 1.7-2 cm; petals entire; lip golden yellow, with margin pale purplish red. |
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21 D. loddigesii |
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Stems not as above; inflorescence 1-3(-6)-flowered, on leafless stems |
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(12) |
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| 12 (11) |
Lip fimbriate, compoundly ciliate; sepals and petals white with purplish red tip; lip reniform- orbicular, white tinged with purplish red at apex, lip disk with a yellow spot on either side. |
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22 D. devonianum |
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Lip not fimbriate, compoundly ciliate; otherwise without above combination of characters |
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(13) |
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| 13 (12) |
Floral bracts 10-12 mm, papery; anther cap with dense long crystal-like papillae; sepals and petals white, usually with a pale purple blotch toward tip; lip orange-yellow tinged with purplish red at apex. |
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25 D. crystallinum |
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Floral bracts 2-8 mm, membranous; anther cap glabrous or finely papillate; sepals and petals white, apex pale purplish red; sepals 2.3-3 cm; lip suborbicular, with purplish red stripes at base on either side, apex pale purplish red, disk yellow |
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(14) |
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| 14 (13) |
Petals conspicuously wider than sepals; flowers pink; stem often slender; peduncle short, arising from nodes. |
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23 D. cucullatum |
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Sepals and petals nearly equal in width or petals wider; flowers white, pink, yellowish, greenish, or brown; stem robust or slender |
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(15) |
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| 15 (14) |
Sepals and petals nearly equal in width; flowers pink; stem robust; peduncle inconspicuous, arising from a cymbiform channel on nodes. |
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24 D. polyanthum |
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Petals usually wider than sepals; flowers white, pale pink, yellowish, greenish, or brown; stem slender |
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(16) |
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| 16 (15) |
Mentum ca. 1 cm, tubular; sepals and petals not spreading; lip densely curled pale yellow villous on disk, margin fimbriate. |
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38 D. xichouense |
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Mentum 5-8 mm, rounded to conic; sepals and petals spreading to recurved; lip with disk glabrous or with purplish hairs, margin entire |
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(17) |
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| 17 (16) |
Bracts without reddish brown mottling; stems 1.5-11 cm; sepals and petals uniformly pale pink or yellowish white with pale pink apex |
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(18) |
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Bracts with transverse reddish brown mottling at base or near middle; stems to 60 cm (rarely less than 10 cm in dwarf plants of D. moniliforme); sepals and petals uniformly white, yellowish green, or brown |
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(19) |
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| 18 (17) |
Stems 6-11 cm, cylindric, distinctly flexuous; sepals and petals yellowish white with pale pink apex, lip with purple at base and along margin and apex. |
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35 D. flexicaule |
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Stems 1.5-3 cm, fusiform-obovoid; sepals and petals uniformly pale lilac-pink, lip with 2 yellowish patches on either side. |
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36 D. wangliangii |
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| 19 (17) |
Sepals and petals recurved, revolute, brown. |
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32 D. fanjingshanense |
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Sepals and petals spreading, ± flat, white or pale greenish cream |
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(20) |
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| 20 (19) |
Dorsal sepal 3-4 cm, lanceolate; lip 2.3-2.5 cm, pale yellow, rarely white; stems 40-70 cm; petals lanceolate. |
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31 D. okinawense |
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Dorsal sepal much shorter, 1.5-2.5 cm, ovate-oblong or lanceolate; lip 1.2-2 cm, varying in color; stems 10-40 cm; petals lanceolate, subelliptic, oblong, or ovate-oblong |
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(21) |
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| 21 (20) |
Flowers white, lip white with a green spot in gullet, or tinged pale rose, usually with a distal purple crescent. |
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30 D. moniliforme |
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Flowers whitish to yellowish or yellowish to greenish, sometimes tinted pink, lip not as above, without a green spot in gullet |
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(22) |
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| 22 (21) |
Inflorescence (1-)3-8-flowered; flowers yellowish to greenish, never tinted pink; anther cap cream, sometimes with purple tip. |
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33 D. catenatum |
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Inflorescence 1-3-flowered; flowers whitish to yellowish, often tinted pink; anther cap wholly bright purple. |
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34 D. scoriarum |
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List of Keys
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List of lower taxa
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