ORCHIDACEAE - China

386EPIDENDROIDEAE● Lithophytic or rarely epiphytic, on limestone; ca. 1200 m. SYunnan (Mengla).This species is known only from a single population with only ca.50 plants.44. Dendrobium chryseum Rolfe, Gard. Chron., ser. 3, 3: 233.1888.线 叶 石 斛 xian ye shi huAporum rivesii (Gagnepain) Rauschert; Callista aurantiacaKuntze; Dendrobium aurantiacum H. G. Reichenbach(1887), not (F. Mueller) F. Mueller (1870); D. aurantiacum var.zhaojuense (S. C. Sun & L. G. Xu) Z. H. Tsi; D. chryseum var.bulangense G. X. Ma & J. Xu; D. clavatum Wallich ex Lindleyvar. aurantiacum Tang & F. T. Wang; D. flaviflorum Hayata; D.rivesii Gagnepain; D. rolfei A. D. Hawkes & A. H. Heller; D.tibeticum Schlechter; D. zhaojuense S. C. Sun & L. G. Xu.Stems cylindric, usually 25–35 cm, slender, 2–4 mm indiam., unbranched, with many nodes, internodes 2.5–4 cm, paleyellow or yellowish brown when dry. Leaves linear or narrowlyoblong, 8–10 × 0.4–1.4 cm, leathery, base sheathing, apex obtuseand emarginate or sometimes subacute and obliquelyhooked; leaf sheath tightly embracing stem. Inflorescence lateralon old leafless stem, ca. 1 cm, usually 1 or 2(or 3)-flowered;peduncle suberect, ca. 0.5 cm; basal sheaths 3 or 4, overlapping,pale white, cupular or tubular, papery, basal ones short,distally elongate, 5–20 mm; floral bracts pale white, cymbiform,12–13 × ca. 5 mm, membranous, apex obtuse. Pediceland ovary ca. 3 cm. Flowers spreading, ca. 6.5 cm wide, concolorousyellow, center a darker shade, occasionally with largepurple spots on sepals and petals and a purple spot on lip disk,inner surface of lip sometimes with several red stripes. Dorsalsepal oblong-elliptic, 23–25 × 11–14 mm, 5-veined, obtuse; lateralsepals slightly obliquely oblong, ca. as long as dorsal sepalor slightly narrower, 5-veined, apex obtuse; mentum conic, ca.6 mm. Petals elliptic or broadly elliptic-obovate, 24–26 × 14–17mm, 3-veined, lateral major veins branched, apex obtuse; lipsuborbicular, ca. 25 × 22 mm, adaxially densely pilose, bothsides embracing column below middle, claw ca. 3 mm, marginirregularly denticulate, disk without markings. Column ca. 4mm, foot ca. 3 mm; anther cap narrowly conic, ca. 4 mm, glabrous,apex subtruncate. Fl. May–Jun. 2n = 38.Epiphytic on tree trunks in high-mountain broad-leaved forests;1700–2600 m. C Sichuan (Ebian, Emei Shan), Taiwan, NW to SEYunnan [NE India, Myanmar].Dendrobium chryseum has been more widely known as D. aurantiacumH. G. Reichenbach but that name is illegitimate because it is alater homonym. Plants from 1700–1800 m in C and S Sichuan andYunnan with pale purple markings on the sepals and a purple spot onthe lip disk have been referred to D. aurantiacum var. zhaojuense.Seidenfaden (Opera Bot. 83. 1985) united two distinct entitiesunder Dendrobium chryseum, namely D. chryseum and D. denneanum(see below).45. Dendrobium denneanum Kerr, J. Siam Soc., Nat. Hist.Suppl. 9: 229. 1933.叠 鞘 石 斛 die qiao shi huCallista clavata Kuntze; Dendrobium aurantiacum H. G.Reichenbach var. denneanum (Kerr) Z. H. Tsi; D. clavatumWallich ex Lindley (1852), not Roxburgh (1832).Stems robust, to 47 cm, more than 4 mm in diam. Leavesoblanceolate, to 11 × 1.8–4.5 cm. Inflorescences subapical onleafless penultimate and older stems, stiffly arching, 5–14 cm,to 7-flowered; floral bracts prominent, 1.8–3 cm. Flowers ca. 5cm wide, orange-yellow, lip with a maroon center or large purplespots on adaxial surface; many clones ± cleistogamous.Epiphytic on tree trunks in open forests; 600–2500 m. W Guangxi,S Guizhou, Hainan (Bawangling), NW to SE Yunnan [India, Laos,Myanmar, Nepal, Thailand, Vietnam].46. Dendrobium jiajiangense Z. Y. Zhu, S. J. Zhu & H. B.Wang, Bull. Bot. Res., Harbin 28: 385. 2008.夹 江 石 斛 jia jiang shi huStems clustered, cylindric, 35–60 cm, slender, 2–5 mm indiam., internodes green or pale yellowish green with whitemembranous leaf sheaths, grooved and angular. Leaf bladelinear or linear-lanceolate, 6–8 × 0.9–1.2 cm, leathery or thinlyso, base narrowed into amplexicaul sheath, apex obtuse orobliquely retuse; leaf sheath with raised veins. Inflorescencelateral on previous year’s leafless stem, ascending, to 6 cm, 1 or2(or 3)-flowered; peduncle 2.5–3 cm; basal sheaths 3 or 4, palepurplish, cupular or tubular, thickly papery, 4–15 mm, withraised veins; floral bracts pale purplish, cymbiform, 15–20 × ca.5 mm, thickly papery, apex obtuse. Pedicel and ovary 1–2.5 cm.Flowers scented, spreading, golden yellow, base of lip purplestriate, disk sometimes golden yellow spotted, anther cap white.Dorsal sepal oblong or oblong-elliptic, 24–26 × 10–11 mm, 6-or 7-veined, apex obtuse; lateral sepals shorter and narrower, 6-or 7-veined, base slightly oblique, apex obtuse; mentum conic,3–4 mm. Petals broadly elliptic or ovate, 14–22 × 11–17 mm,3-veined, lateral major veins branched, apex rounded; lipbroadly ovate, 17–21 × 21–22 mm, adaxially densely tomentose,with claw 3–4 mm, margin irregularly denticulate. Column4–5 mm, foot ca. 3 mm; anther cap conic, front margintoothed.● 1000–1300 m. Sichuan.This species is known to us only from the protologue.47. Dendrobium fimbriatum Hooker, Exot. Fl. 1: ad t. 71.1823.流 苏 石 斛 liu su shi huCallista fimbriata (Hooker) Kuntze; C. oculata (Hooker)Kuntze; Dendrobium fimbriatum var. oculatum Hooker; D.paxtonii Paxton.Stems rigid, decumbent or pendulous, cylindric or sometimesslightly fusiform above base, 50–100 cm, stout, 8–12(–20) mm in diam., unbranched, with many nodes, internodes3.5–4.8 cm, longitudinally grooved, pale yellow or paleyellowish brown when dry. Leaves oblong or oblong-lanceolate,8–15.5 × 2–3.6 cm, leathery, with tightly clasping leatherysheaths at base, apex acute, sometimes slightly bilobed. Inflorescencesracemose, 5–15 cm, laxly 6–12-flowered; peduncle