Dendrobium draconis Rchb.

Averyanov, Leonid V., Ponert, Jan, Nguyen, Phi Tam, Duy, Nong Van, Khang, Nguyen Sinh & Nguyen, Van Canh, 2016, A survey of Dendrobium Sw. sect. Formosae (Benth. & Hook. f.) Hook. f. in Cambodia, Laos and Vietnam, Adansonia 38 (2), pp. 199-217 : 206

5. Dendrobium draconis Rchb. f.

Botanische Zeitung 1862: 214 (1862); Gagnep., Flore générale de l’Indo-Chine 6 (2): 228 (1933); Seidenf., Opera Botanica 83: 110, fig.66, table 14d, fig. 66, table 14d (1985); 114: 211 (1992). — Aver., Identification Guide to Vietnamese Orchids: 182 (1994). — P.H.Ho, An Illustrated Flora of Vietnam 3: 826, fig. 11058 (2000). — Aver. & Averyanova, Updated Checklist of the Orchids of Vietnam: 27 (2003). — Newman et al., A Checklist for the Vascular Plants of Lao: 263 (2007). — Schuiteman et al., Nordic Journal of Botany 26: 282 (2008). — Aver., Turczaninowia 16 (4): 34 (2013).

Dendrobium eburneum Batem. , Botanical Magazine 90: table 5459 (1864).

TYPUS. — Myanmar. Moulmein , Parish 131, 132b, Herb. Reichenbach 32379 (holo-, W).

HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte on tall trees in primary and secondary dry lowland evergreen and semi-deciduous forests and woodlands, often on thin ferralitic soils. 200-1000 m. Fl. January-May. Rare. Expected IUCN Red List status – EN.

DISTRIBUTION. — Cambodia (Kampong Speu, Kampong Thom, Steung Treng ) , Laos (Attopeu, Champasak, Savannakhet, Vientiane) , Vietnam (Da Nang, Dak Lak, Khanh Hoa, Lam Dong) . NE India, Myanmar, Thailand .

MATERIAL EXAMINED. — Cambodia. Kampong Speu, Cardamom Mountains, Phnom Aural mt., T.Maisak et al., 944 ( LE); Kompong Speu, sud de Chambok, Poilane 17453 ( P [ P 00407628]); Kampong Thom, entre Romchek et Pring, Poilane 14826 ( P [ P 00407626, P 00407627]).

Laos. Attapu, Harmand 1404 ( P [ P 00407630, P 00407631]); Champasak, Paksane road km 25, A.D.Kerr 698, 705 ( C); Savannakhet ,, Muong Phinh, Poilane 11489 ( P [ P 00407635]); Savannakhet, Poilane 11528 ( P [ P 00407634]), 13341 bis 26 ( P [ P 00407633]); Vientiane, A.D.Kerr 695 ( C); Laos, Phu Kedan, Brix s.n. ( C).

Vietnam. Da Nang,Tourane, Mt.Bana, Clemens 3905 ( P [ P 00407641]); Dak Lak, Ban Don, HLF 7167a, HLF 7347 ( HN, LE, MO); Lam Dong, Bidoup, Ht. Donai, Poilane 31050 ( P [ P 00407643], W); Lam Dong, Brian, Poilane 24345 ( P [ P 00407642]); Lam Dong, Dalat, CRST 291 ( P [ P 00407640]); Lam Dong, Dalat, L.Averyanov s.n. anno 2004 ( LE photo); Lam Dong, entre Dankia et Danglê, Poilane 23572 ( P [ P 00407647]); Lam Dong, Fimnon, région de Dalat, Lichy s.n. ( P [ P 00386031]); Lam Dong, Lang Bian, entre Bellevue et Dran, Chevalier 40402 ( P [ P 00386230]); Vietnam, Cochinchine sine loc., Thorel s.n. ( P [ P 00407636, P 00407637]); Vietnam, sine loc., Boden Kloss, s.n. ( BK); Vietnam, central regions, sine loc., HAL 12851 B ( LE, P photo, K photo, LOC photo).

DESCRIPTION

Stems cylindrical to narrowly fusiform, (10)15-40(50) cm long, 0.8-1.5 cm in diameter, of many nodes. Leaves ovate to oblong narrowly ovate, 5-10 cm long, 1.5-2.5 cm wide. Inflorescences 1-4(5), each with 1-3(5) flowers. Pedicel and ovary 2.5-3.5 cm long. Flowers tangerine fragrant, widely opening, 4-6 cm across, white, disc and base of the lip bright red, sometimes adaxially yellow. Sepals and petals narrowly ovate, acute 2.5-3.5 cm long, 0.6-1 cm wide; petals slightly wider; mentum narrowly conical to cylindrical, spur-like, curved, 2-2.5 cm long, 2-4 mm in diameter. Lip narrowly ovate, 3-lobed, slightly shorter than sepals, 1.4-1.6 cm wide; side lobes small, half circular, as long as column; median lobe narrowly ovate to ovate, acute to acuminate, much longer than side lobes, strongly undulate and irregularly denticulate along margin; disc with 3-5 low indistinct verruculose keels. Column white, 7-9 mm tall ( Fig. 1H ).

REMARK

In the past, it was the most common species of the section all over southern Indochina. Presently it has become endangered in all countries of the region due to wide deforestation and degradation of its native habitats at low elevations.

Figures

FIG. 1. — A, B, Dendrobium bellatulum Rolfe; A, VH 2566; B, VH 2567; C, D, D. christyanum Rchb.f.; C, VH 950; D, CPC 6038; E, D. scabrilingue Lindl. (Konstantinov 29); F, G, D. suzukii T.Yukawa; F, Duy s.n., III.2014; G, L.Averyanov s.n., XI.2013); H, D. draconis Rchb.f. (HLF 7347); I, D. kontumense Gagnep.(LA-VN 21a). Photos: A-D, G-I, L. Averyanov; E, E. Konstantinov; F, N.V. Duy.