Dendrobium daklakense Tich, Schuit. & J.J.Verm.

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 : 208-209

8. Dendrobium daklakense Tich, Schuit. & J.J.Verm.

Orchideen Journal 17: 161 (2010).

TYPUS. — S Vietnam. Dak Lak province. Flowering in cultivation XI.2009, number N. T. Tich 20.11.09 (holo-, VNM, Herbarium of Department of Botany and Ecology – Faculty of Natural Science – National University of Vietnam, Ho Chi Minh City) .

HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte on trees in evergreen broad-leaved submontane forests. 500-800 m. Fl. October - December. Very rare. Expected IUCN Red List status – CR .

DISTRIBUTION. — Vietnam (Kontum and presumably Dak Lak). Local endemic .

MATERIAL EXAMINED. — Vietnam. Dak Lak, sine loc., P. T . Nguyen , s.n., X.2014 ( LE photo) ; Dak Lak, Buon Ma Thuot City market, V. Q . Binh & L . Averyanov , s.n., 7.XI.2014 ( LE photo) ; Dak Lak, Buon Ma Thuot City market, L . Averyanov & P. T . Nguyen , s.n., 3.XII.2014, LE ); Kontum, Dak Gley , Lo So Deo Pass., Quach Van Hoi, V. C . Nguyen & L . Averyanov , CPC 7696 , 5.XII.2014 ( LE) ; Kontum, Dak Gley , Lo So Deo Pass., XI.2015, V. V . Cong , s.n. ( LE photo) .

DESCRIPTION

Stems cane-like to narrowly fusiform, 0.4-0.6 m tall, 5-8 mm in diameter, of many nodes; internodes 3.5-4.5 cm long. Leaves narrowly ovate to oblong-lanceolate, 7-9 cm long, 1.8-2.2 cm wide, unequally bilobed, largest lobe acuminate. Inflorescences 1-3, terminal and axillary, with (3)5-7 flowers; floral bracts triangular lanceolate, acuminate, 8-10 mm long. Pedicel and ovary white, 2.8-3 cm long. Flowers widely opening, 4-5 cm across; sepals and petals pure white; lip uniform orange-yellow. Sepals triangular narrowly ovate, mucronate, dorsally keeled 2-2.5 cm long, 8-12 mm wide; mentum broadly conical, 1-1.2 cm long. Petals broadly rhomboid, mucronate, 2-2.2 cm long, 1.2-1.5 cm wide. Lip deeply 3-lobed, 2.8-3 cm long, 2-2.2 cm wide, shortly clawed at base; side lobes erect, triangular ovate, 1 cm long and wide, finely denticulate, orange-red striped inside; median lobe narrowly rhomboid, 1 cm long, 4 mm wide at the middle, attenuate to mucronate apex; disc papillose, with erect retrorse, emarginate-globose callus spreading to median lobe in form of thick fleshy verruculose band. Column 6-7 mm tall, 3 mm wide, white verrucose; anther cap white, cubic, 2.5 mm tall and wide ( Fig. 2C, D ).

REMARK

Extremely rare, a taxonomically isolated species known only from a single verified location in Kontum province ( Fig. 2C ). Its putative occurrence in Dak Lak province needs confirmation. It is highly probable that species stands on the verge of its full extinction in the wild due to deforestation and commercial collecting supported by high market demands.

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.