Oberonia in Flora of China @ efloras.org

81. Oberonia Lindley, Gen. Sp. Orchid. Pl. 15. 1830.

鸢尾兰属 yuan wei lan shu

Authors: Xinqi Chen, Paul Ormerod & Jeffrey J. Wood

Iridorkis Thouars (1809), not Iridorchis Blume (1859); Titania Endlicher.

Herbs, epiphytic. Stems often enclosed in leaf base, usually clustered, rarely borne on an elongate rhizome, erect or pendulous, short or somewhat elongate. Leaves iridiform and unifacial, rarely terete, often fleshy, articulate or not at base, distichous, usually equitant, often imbricate at base, often dilated near base into flattened sheaths, often with a narrow membranous margin on adaxial side in basal half. Inflorescences terminal, racemose, unbranched, pubescent or glabrous, usually many flowered; peduncle often with sterile bracts below; floral bracts persistent, often erose. Flowers often in whorls, not resupinate, flat, very small, usually only 1-2 mm in diam.; ovary glabrous or papillate. Sepals and petals free, spreading, petals often narrower than sepals, sometimes erose; lip usually spreading, sessile, entire or lobed, margin sometimes erose or fimbriate, occasionally concave at base, with or without calli, spur absent; lateral lobes often embracing column. Column erect, short, lacking a foot, wings usually absent; anther cap terminal, firmly attached to column apex, 2-locular; pollinia 4, cohering in 2 unequally sized pairs, waxy; viscidium absent or abbreviated; stigma transversely reniform to ovate; rostellum protruding.

Between 150 and 200 species: centered in tropical S and SE Asia but extending to tropical Africa, Madagascar, the Mascarene Islands, the Philippines, New Guinea, NE Australia, and the SW Pacific islands across to Tahiti; 33 species (11 endemic) in China.

Oberonia teres Kerr (Bull. Misc. Inform. Kew 1927: 214. 1927), formerly considered endemic to Thailand, was recorded from W Yunnan (Lushui: Gaoligong Shan, ca. 2400 m) by X. H. Jin, H. Li, and D. Z. Li (Acta Phytotax. Sin. 45: 805-806. 2007). The present authors could not confirm this because they have not seen the specimen (X. H. Jin 7029, PE).

1 Rhizome elongate, to 7 cm or more, leafy stems arising at intervals of 2-25 mm along rhizome (2)

+ Rhizome abbreviated (4)

2 (1) Leaves not articulate at base; petals linear, slightly falcate; leaves 10-25 × 3-8 mm; stems arising at intervals of 5-25 mm along rhizome. 1 O. pumila

+ Leaves articulate to basal sheath; petals, leaves, and stems without above combination of characters (3)

3 (2) Leaves 4-7 mm wide; flowers greenish, sometimes tinged purple; lateral lobes of lip obscurely erose-denticulate. 2 O. seidenfadenii

+ Leaves 1.5-2 mm wide; flowers pale yellowish brown; margins of lip irregularly serrate. 3 O. sinica

4 (1) Leaves not articulate at base (5)

+ Leaves articulate at base (17)

5 (4) Peduncle connate in lower part to uppermost leaf, appearing to arise from leaf blade. 15 O. obcordata

+ Scape not connate in lower part to uppermost leaf (6)

6 (5) Mid-lobe of lip bilobed, with sinus more than 1/5 length of lip; lobules acuminate to long acuminate at apex (7)

+ Mid-lobe of lip entire or shallowly lobed at apex, with sinus less than 1/6 length of lip; lobules obtuse at apex (11)

7 (6) Stem very short or inconspicuous; leaves nearly basal; flowers red; lip with a callus near base (8)

+ Stem 1.5-7 cm; leaves cauline, distichous; flowers green to orange-yellow, sometimes pale red; lip without callus (9)

8 (7) Lateral lobes of lip orbicular; peduncle bracts lanceolate. 14 O. recurva

+ Lateral lobes of lip filiform; peduncle bracts filiform. 13 O. rufilabris

9 (7) Lateral lobes of lip ± erose or erose-fimbriate on margin. 16 O. arisanensis

+ Lateral lobes of lip entire (10)

10 (9) Leaves 1-2(-3) mm wide; flowers greenish yellow or pale yellow; petals slightly longer than sepals. 11 O. mannii

+ Leaves 3-5 mm wide; flowers pale red; petals and sepals equal in length. 12 O. anthropophora

11 (6) Floral bracts 4-5 mm, more than 3 × as long as pedicel and ovary. 8 O. longibracteata

+ Floral bracts 1-2 mm, less than 3 × as long as pedicel and ovary (12)

12 (11) Petals conspicuously erose at margin; lateral lobes of lip slightly smaller than mid-lobe. 7 O. rosea

+ Petals entire or inconspicuously erose at margin (13)

13 (12) Lateral lobes of lip ca. as large as or slightly larger than mid-lobe, margins erose, irregularly laciniate, or fimbriate. 6 O. jenkinsiana

+ Lateral lobes of lip conspicuously smaller than mid-lobe, margins entire or inconspicuously erose (14)

14 (13) Sepals broader than petals (15)

+ Sepals and petals equal in width (16)

15 (14) Stem conspicuous, 1-2 cm; leaf blade 1-2(-3) cm; pedicel and ovary nearly as long as or slightly longer than floral bracts. 4 O. japonica

+ Stem inconspicuous; leaf blade 2.5-7 cm; pedicel and ovary shorter than floral bracts. 5 O. variabilis

16 (14) Mid-lobe of lip obtuse at apex; lateral lobes subovate or ovate-oblong; petals inconspicuously erose at margin. 10 O. menghaiensis

+ Mid-lobe of lip emarginate at apex; lateral lobes nearly narrowly ovate-lanceolate; petals entire. 9 O. delicata

17 (4) Leaves subterete. 33 O. cavaleriei

+ Leaves laterally compressed (18)

18 (17) Leaves 20-50 × 1.2-2.2 cm; lip with a callus at either side of sinus. 32 O. ensiformis

+ Leaves commonly 1-20 cm; lip ecallose (19)

19 (18) Peduncle foliaceous below, ± connate to uppermost leaf; lip entire. 31 O. pachyrachis

+ Peduncle cylindric or compressed cylindric, never connate to leaves (20)

20 (19) Petals conspicuously larger than lip, to 2 mm wide. 29 O. latipetala

+ Petals smaller than or nearly as large as lip, less than 1 mm wide (21)

21 (20) Lip entire, nearly oblate. 30 O. integerrima

+ Lip ± 3-lobed, never oblate (22)

22 (21) Floral bracts with a long apical awn. 19 O. falconeri

+ Floral bracts without a long apical awn (23)

23 (22) Scape with narrow wings on both sides, including wings 4-5 mm wide; leaves 1-2.1 cm wide (24)

+ Scape wingless or nearly so, 2-3 mm in diam.; leaves 2-10 mm wide (excluding O. gigantea) (28)

24 (23) Lip nearly entire, retuse, margin irregularly laciniate. 22 O. segawae

+ Lip 3-lobed, apex entire or lobed (25)

25 (24) Mid-lobe of lip unlobed at apex. 27 O. menglaensis

+ Mid-lobe of lip 2-lobed at apex (26)

26 (25) Petals entire. 21 O. gigantea

+ Petals with erose-toothed margins (27)

27 (26) Raceme densely flowered, with several hundred flowers borne less than 1 mm apart from each other. 25 O. mucronata

+ Raceme laxly flowered, flowers to 100, sometimes more, borne up to 3 mm apart from each other. 26 O. gammiei

28 (23) Lateral lobes of lip fimbriate at margin. 28 O. austroyunnanensis

+ Lateral lobes of lip never fimbriate at margin (29)

29 (28) Lobules of mid-lobe of lip subquadrate or broadly oblong, equal in width and length, erose at margin (30)

+ Lobules of mid-lobe of lip oblong or triangular to lanceolate, longer than wide, nearly entire (31)

30 (29) Leaves ca. 13 cm; flowers whorled; lateral lobes of lip very small or inconspicuous. 23 O. kwangsiensis

+ Leaves 1-3.5 cm; flowers scattered; lateral lobes of lip conspicuous. 24 O. cathayana

31 (29) Leaves 1.5-6(-8) × 0.2-0.7 cm; raceme 2-8 cm; lateral lobes of lip conspicuous (32)

+ Leaves (4.5-)8-20 × 0.7-1.5 cm; raceme more than 10 cm; lateral lobes of lip inconspicuous (33)

32 (31) Stem conspicuous, longer than leaves; leaves 2-4 mm wide. 17 O. caulescens

+ Stem often inconspicuous, shorter than leaves when present; leaves (3-)4-7 mm wide. 18 O. pyrulifera

33 (31) Flowers greenish white; mid-lobe of lip with suboblong lobules; leaves 7-10 mm wide, veins conspicuous when dried. 20 O. acaulis

+ Flowers orange; mid-lobe of lip with triangular lobules; leaves 8-15 mm wide, veins inconspicuous when dried. 21 O. gigantea

List of lower taxa

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