Dendrobium roseiodorum

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 : 208

7. Dendrobium roseiodorum

Sathap., T.Yukawa & Seelanan

Blumea 55: 77, figs 1, 2a, b (2010).

Dendrobium kontumense auct. non Gagnep.: T.Yukawa, Annals of the Tsukuba Botanical Garden 23: 23, figs 3, 4 (2004).

TYPUS. — Vietnam. Vietnam, sine loc., Hort.Tsukuba Botanical Garden accession number 118269, 15.IX.2008 (holo-, TNS; iso-, BCU) . HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte in primary evergreen broad-leaved and mixed mountain forests. 1000- 1200 m. Fl. September-November (in cultivation July to December). Very rare. Expected IUCN Red List status – EN.

DISTRIBUTION. — Vietnam : (Khanh Hoa, Lam Dong). Endemic. MATERIAL EXAMINED. — Vietnam. Khanh Hoa, Massif de Cô Inh près Nhatrang , Poilane 4633 ( P [ P00407646 ]); Lam Dong, Dalat area, L . Averyanov s.n., X.2005 ( LE photo); Lam Dong, Duc Trong, Border with Binh Thuan province, 4.XII.2015, P. T . Nguyen , AL 144 ( LE) .

DESCRIPTION

Stems narrowly fusiform, 30-40 cm long, 1-1.4 cm in diameter, of many nodes. Leaves oblong lanceolate, to narrowly ovate, (4)6-9(11) cm long, 1-2 cm wide. Inflorescences 1-2(3), each with (1)2-5 flowers; floral bracts ovate-triangular, acuminate, 1 cm long, 4-7 mm wide. Pedicel and ovary white, 3.2-4.1 cm long, curved. Flowers widely opening, white, sweet fragrant, 4-5.5 cm across, disc red-orange to orangeyellow. Sepals triangular narrowly ovate, acuminate, slightly recurved, 2.5-3.5 cm long, 1-1.4 cm wide, abaxially distinctly keeled. Petals rhomboid obovate, a little wider than sepals, 2.6-3.2 cm long, 1.4-1.6 cm wide, often slightly recurved, undulate along margin. Lip pandurate, 3-lobed, 4-5 cm long, 1.5-2 cm wide, clawed at the base; side lobes half circular, erect; median lobe broadly obovate, undulate along margin, emarginate; disc thick, verruculose, without distinct keels. Mentum narrowly conical, straight to slightly upcurved, 2.5- 3 cm long, 2.5-3 mm diameter. Column yellowish, 7-8 mm tall, 5.5-6.5 mm wide; anther cap light yellowish, cucullate 3 mm tall and wide, papillose ( Fig. 2B ).

REMARK

A questionable taxon known mainly on the basis of cultivated specimens of unknown origin. It is very close to D. kontumense , from which it differs in the rugose disc of the lip without distinct keels, and the strong, rose-like fragrance. This taxon has first been separated from D. kontumense in 2010 and these two taxa are still widely misidentified in orchid collections.

Figures

FIG. 2. — A, Dendrobium kontumense Gagnep.(L.Averyanov s.n., X.2005);B, D. roseiodorum Sathap.,T.Yukawa & Seelanan (L.Averyanov s.n., X.2005);C, D, D. daklakense Tich,Schuit. & J.J.Verm.; C, Vo Van Cong, s.n., XI.2015; D, V.Q.Binh & L.Averyanov, s.n., 7.XI.2014; E, D. infundibulum Lindl. (L.Averyanov s.n., Thailand, Chiangmai, 2002); F, G, D. wattii (Hook.f.) Rchb.f.; F, L.Averyanov s.n., XI.2013; G, HAL 8630; H, D. multilineatum Kerr (LA-VN 256). Photos: A-G, L. Averyanov; H, N. S. Khang.