Flora of China 25: 236–245. 2009. 81. OBERONIA Lindley, Gen. Sp. Orchid. Pl. 15. 1830, nom. cons. 鸢尾兰属 yuan wei lan shu Chen Xinqi (陈心启 Chen Sing-chi); 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). 1a. Rhizome elongate, to 7 cm or more, leafy stems arising at intervals of 2–25 mm along rhizome. 2a. 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 2b. Leaves articulate to basal sheath; petals, leaves, and stems without above combination of characters. 3a. Leaves 4–7 mm wide; flowers greenish, sometimes tinged purple; lateral lobes of lip obscurely erose-denticulate .............................................................................................................................................. 2. O. seidenfadenii 3b. Leaves 1.5–2 mm wide; flowers pale yellowish brown; margins of lip irregularly serrate ....................................... 3. O. sinica 1b. Rhizome abbreviated. 4a. Leaves not articulate at base. 5a. Peduncle connate in lower part to uppermost leaf, appearing to arise from leaf blade ..................................... 15. O. obcordata 5b. Scape not connate in lower part to uppermost leaf. 6a. Mid-lobe of lip bilobed, with sinus more than 1/5 length of lip; lobules acuminate to long acuminate at apex. 7a. Stem very short or inconspicuous; leaves nearly basal; flowers red; lip with a callus near base. 8a. Lateral lobes of lip orbicular; peduncle bracts lanceolate ............................................................................ 14. O. recurva 8b. Lateral lobes of lip filiform; peduncle bracts filiform ............................................................................... 13. O. rufilabris 7b. Stem 1.5–7 cm; leaves cauline, distichous; flowers green to orange-yellow, sometimes pale red; lip without callus. 9a. Lateral lobes of lip ± erose or erose-fimbriate on margin ...................................................................... 16. O. arisanensis 9b. Lateral lobes of lip entire. 10a. Leaves 1–2(–3) mm wide; flowers greenish yellow or pale yellow; petals slightly longer than sepals ................................................................................................................................................ 11. O. mannii 10b. Leaves 3–5 mm wide; flowers pale red; petals and sepals equal in length ............................... 12. O. anthropophora 6b. Mid-lobe of lip entire or shallowly lobed at apex, with sinus less than 1/6 length of lip; lobules obtuse at apex. 11a. Floral bracts 4–5 mm, more than 3 × as long as pedicel and ovary .................................................... 8. O. longibracteata 11b. Floral bracts 1–2 mm, less than 3 × as long as pedicel and ovary. 12a. Petals conspicuously erose at margin; lateral lobes of lip slightly smaller than mid-lobe ............................. 7. O. rosea 12b. Petals entire or inconspicuously erose at margin. 13a. Lateral lobes of lip ca. as large as or slightly larger than mid-lobe, margins erose, irregularly laciniate, or fimbriate .......................................................................................................................... 6. O. jenkinsiana 13b. Lateral lobes of lip conspicuously smaller than mid-lobe, margins entire or inconspicuously erose. 14a. Sepals broader than petals. 15a. 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 15b. Stem inconspicuous; leaf blade 2.5–7 cm; pedicel and ovary shorter than floral bracts ............... 5. O. variabilisFlora of China 25: 236–245. 2009. 14b. Sepals and petals equal in width. 16a. Mid-lobe of lip obtuse at apex; lateral lobes subovate or ovate-oblong; petals inconspicuously erose at margin ............................................................................................ 10. O. menghaiensis 16b. Mid-lobe of lip emarginate at apex; lateral lobes nearly narrowly ovate-lanceolate; petals entire ........................................................................................................................................ 9. O. delicata 4b. Leaves