Dendrobium longicornu Lindl.

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 : 214

14. Dendrobium longicornu Lindl.

The Genera and Species of Orchidaceous Plants: 80 (1830); Edwards’s Botanical Register 16, table 1315 (1830). — King & Pantl., Annals of the Royal Botanic Garden, Calcutta 8,table 64 (1898). — Gagnep., Flore générale de l’Indo-Chine 6 (2): 250 (1933). — Seidenf., Opera Botanica 114: 219, fig. 139, table 13d (1992). — Aver., Identification Guide to Vietnamese Orchids: 181 (1994). — P.H.Ho, An Illustrated Flora of Vietnam 3: 828, fig. 11064 (2000). — Pearce & Cribb, The Orchids of Bhutan: 417 (2002). — Aver. & Averyanova, Updated Checklist of the Orchids of Vietnam: 29 (2003). — Zhu Guanghua et al., Flora of China 25: 392 (2009).

TYPUS. — Bangladesh and Nepal. Sylhet et Napalia , F. De Silva Wall. Cat. 1997.2 (syn-, K [ K000718659 ]) ; Wallich Wall.Cat. 1997.1 (syn-, K [ K000894403 ]; isosyn-, P [ P00407980 ]) .

HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte on big trees and occasionally lithophyte on mossy rocky cliffs in primary and secondary evergreen, broad-leaved, mixed and coniferous humid shady mountain forests on any kind of soils, commonly on steep rocky slopes and on mountain tops. 1000-2100 m. Fl.September-December. Not rare, locally abundant. Expected IUCN Red List status – VU.

DISTRIBUTION. — Vietnam (Cao Bang, Dien Bien, Ha Giang, Lai Chau, Lao Cai, Nghe An, Son La,Tuyen Quang, Vinh Phuc). Bhutan, Nepal ., NE. India, Myanmar , S. China .

MATERIAL EXAMINED. — Vietnam. Cao Bang, Bao Lac, Ca Thanh, CBL 404 ( HN, LE, MO, P [ P02103759 ]); Cao Bang, Bao Lac, Dinh Phung, CBL 1546 ( HN, LE, MO); Cao Bang, Bao Lac, Yen Lac, CBL 317 ( HN, LE, MO); Cao Bang, Nguyen Binh, Ca Thanh, CPC 5378 ( CPC Herbarium , LE); Dien Bien, L . Averyanov s.n., XII.2010 ( LE photo); Ha Giang, Bac Me, Phieng Luong, HAL 6429 ( HN); Ha Giang, Dong Van, Ho Quang Phin, CBL 1805 ( HN, LE, MO); Ha Giang, Hoang Su Phi , Ho Thau , HAL 6703 ( HN, LE); Ha Giang, Meo Vac , Shung Cha , NTH 3309 ( HN); Ha Giang, Quan Ba , Bat Dai Son , V . Thao 47 ( HN), DKH 5228 ( HN, LE, MO); Ha Giang, Vi Xuyen, Cao Bo, DKH 5596 ( HN, LE, MO); Ha Giang, Yen Minh, Lao Va Chai, HAL 8408 ( HN, MO), NTH 3460 ( HN, LE); Lai Chau, Sin Ho , Ma Quai , HAL 9946 ( HN, LE); Lao Cai, Chapa , Pételot s.n. ( P [ P00408318 ]); Lao Cai, O Quy Ho passes, D.Bui & C . X.Canh s.n. anno 2014 ( LE photo); Lao Cai, Sa Pa, L . Averyanov s.n., 24.XI.2005 ( LE photo); Lao Cai, Van Ban, Khanh Yen Ha, HAL 2417 ( HN, LE); Nghe An, Ky Son, Na Ngoi, Phu Xai Lai Leng mt. , CPC 6322 ( CPC Herbarium , LE); Nghe An, Tuong Duong , Tam Hop , HLF 6936 ( HN, LE, MO); Son La, Thuan Chau , Phong Lai , Pha Din Pass , DKH 5677 ( HN, LE, MO); Tuyen Quang, Na Hang , Sinh Long , CPC 5302 ( CPC Herbarium , LE), CPC 4544 a ( LE photo); Vinh Phuc, Tamdao, LX- VN 1395 ( HN, LE), LX-VN 2367 ( HN, LE), Vu 19934 ( HN); Lao Cai, Sa Pa , Hoang Lien Range, N. A . Duc et al., HL 137 ( HNU, LE) .

DESCRIPTION

Stems cylindric, rather slender, reed-like, ascending to pendulous, 10-35(40) cm long, 3-5 mm in diameter, of many nodes, internodes 1.5-4 cm long. Leaves oblong lanceolate, 3-7 cm long, 0.5-1.5 cm wide. Inflorescences 1-3, each with 1-3(4) flowers; floral bracts broadly lanceolate, acute, 5-8 mm long. Pedicel and ovary 2-3(3.5) cm long. Flowers light sweet fragrant, pendulous, white, campanulate, not widely opening, 2-3 cm across, disc and lip apex yellow-pink to orange. Sepals and petals subsimilar, triangular narrowly ovate, acute, 1.5- 2.2 cm long, 5-8 mm wide, sepals distinctly keeled abaxially. Mentum long, cylindric, straight, spur-like, as long as pedicel and ovary or little longer, 1.5-2.5 mm in diameter. Lip broadly obovate rhombic, (2) 2.4-3.5 cm long, 1.8-3 cm wide, apex entire to indistinctly 3-lobe; median lobe irregularly dentate or fringed, sometime indistinctly emarginate; disc naked or sparsely setose along veins, with 3-7 low insignificant keels. Column 5-6 mm tall; anther cap conical, at front almost flat, apically truncate ( Fig. 3G, H ).

REMARK

Existing records in the literature for this species for southern Vietnam (Lam Dong, Dalat; Lang Bian, 2000 m; Lac Duong) belong probably to Dendrobium wattii ( Seidenfaden 1992: l.c.: 219).

Figures

FIG. 3. — A, Dendrobium multilineatum Kerr (LA-VN 256); B-D, Dendrobium williamsonii Day & Rchb.f. (CPC 24290); E, F, D. cariniferum: Rchb.f.; E, VH 2256a; F, HLF 5500a; G, H, D. longicornu Lindl. (CPC 5378); I, D. chapaense Aver. (N.A.Duc et al., HL 131). Photos: A, N. S. Khang; B-H, L. Averyanov; I, N. A. Duc.