Dendrobium ochraceum De Wild.

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 : 215

16. Dendrobium ochraceum De Wild.

La Tribune horticole 1: 41 (1906). — Seidenf., Opera Botanica 83: 124, fig. 78 (1985); 114: 219, fig. 140, table 14a (1992). — Aver., Identification Guide to Vietnamese Orchids: 182 (1994). — P.H.Ho, An Illustrated Flora of Vietnam 3: 827, fig. 11060 (2000). — Aver. & Averyanova, Updated Checklist of the Orchids of Vietnam: 29 (2003).

TYPUS. — N Vietnam. Tonkin, Bronckart s.n. (holo-, BR).

HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte on tall trees in primary and secondary lowland evergreen broad-leaved and mixed rather dry forests on granite, sandstone, quartzite and shale, commonly on steep rocky slopes and on mountain tops. (200) 400-800 m. Fl. March-May (June). Rare. Expected IUCN Red List status – EN. DISTRIBUTION. — Vietnam (Gia Lai, Ha Tinh, Quang Nam, Thu Thien-Hue). Endemic .

MATERIAL EXAMINED. — Vietnam. Gia Lai, Kon Ha Nung, Kbang, L.Averyanov LX-VN 0/61 anno 1985 ( LE, LE photo); Gia Lai, Kbang, Tram Lap, L.Averyanov LX-VN s.n., anno 1989 ( LE); Ha Tinh, Huong Son, Son Kim, HAL 1365 ( HN, LE, LE photo); Quang Nam, Dai Loc, Dai Hong, CPC 3576 ( CPC Herbarium, LE, LE photo); Thu Thien-Hue, A Luoi, H.Nguyen, CPC 3142 ( CPC Herbarium, LE); Thu Thien-Hue, Nui Bach Ma, Poilane 27663 ( P [ P 00408305]), 29942 ( P [ P 00408304]); Thua Thien-Hue, Huong Thuy, Duong Hoa, HAL 8056 ( HN, LE, LE photo); Thua Thien-Hue, Nam Dong, Thuong Lo, HAL 11125 ( HN, LE, LE photo, MO); Vietnam, Tonkin sine loc., Bronckart s.n. ( BR).

DESCRIPTION

Stems narrowly fusiform, stout, erect, (12)15-60(70) cm long, 0.8-1.5 cm in diameter, of many nodes. Leaves narrowly ovate to oblong lanceolate, (4)5-8(10) cm long, 1.2-2.4 cm wide. Inflorescences 1-5, each with 1-4(5) flowers; floral bracts ovate, acute, to 1.2 cm long. Pedicel and ovary 3.5-4.5(5.5) cm long. Flowers odorless, light yellowish to almost white, widely opening, 3-4.5 cm across, lip with numerous bright red nerves. Sepals and petals subsimilar, triangular narrowly ovate, acuminate, 2.2-2.6(3) cm long, 6-8(10) mm wide, more or less recurved, petals commonly irregularly undulate along margin. Mentum narrowly conical, straight, nearly twice shorter as pedicel and ovary, 1.5-2 cm long, 2.5-3 mm in diameter. Lip pandurate, 3-lobed; 2.2-3 cm long, 1.6- 2.2 cm wide; side lobes half circular, suberect; median lobe half circular to broad squarish, strongly undulate along margin, often indistinctly emarginate; disc with 4 indistinct, low red keels running above veins. Column white, 5-7 mm tall, 3-5 mm wide; anther cap white, at front almost flat, apically truncate ( Fig. 4D, E ).

REMARK

A very distinct species, easy recognized for its flowers having a pale yellowish lip with numerous bright red contrasting veins and strongly recurved irregularly undulating petals.

Figures

FIG. 4. — A-C, Dendrobium chapaense Aver. (25.XI.2015, L.Averyanov s.n.); D, E, D. ochraceum De Wild.; D, CPC 3576; E, HAL 8056; F, G, D. trankimianum T.Yukawa; F, Hon Giao, J.Ponert et al., s.n.; G, L.Averyanov s.n., 2005; H, D. senile E.C.Parish & Rchb.f. (L.Averyanov s.n., IV.2011); I, D. trigonopus Rchb.f. (CPC 1141a). Photos: A-E, G-I, L. Averyanov; F, J. Ponert.