Dendrobium infundibulum 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 : 209

9. Dendrobium infundibulum Lindl.

Journal of the Proceedings of the Linnean Society, Botany 3: 16 (1858). — Gagnep., Flore générale de l’Indo-Chine 6 (2): 229 (1933).— Seidenf., Opera Botanica 83: 117, fig.72, table 15c (1985); 114: 215 (1992). — P.H.Ho, An Illustrated Flora of Vietnam 3: 827, fig. 11062 (2000). — Aver. & Averyanova, Updated Checklist of the Orchids of Vietnam: 28 (2003). — Newman et al., A Checklist for the Vascular Plants of Lao: 263 (2007). — Schuiteman et al., Nordic Journal of Botany 26: 284 (2008).

Dendrobium formosum auct. non Roxb. ex Lindl. (1830): Seidenf., Opera Botanica 83: 111, fig. 67, table 15a (1985). — Aver., Identification Guide to Vietnamese Orchids: 183 (1994). — P.H.Ho, An Illustrated Flora of Vietnam 3: 827, fig. 11059 (2000). — Aver. & Averyanova, Updated Checklist of the Orchids of Vietnam: 27

(2003), p.p. TYPUS. — Myanmar. Moulmein , at 5000 feet on Thoung-gyun ,

T. Lobb s.n. (holo-, K[K000943882]).

HABITAT, PHENOLOGY AND CONSERVATION STATUS. — Epiphyte on tall trees in primary and secondary montane forests, particularly on mountain tops. (1200) 1500-2400 m. Fl. February, March, May,

November-January. Rare. Expected IUCN Red List status – DD. Data on ecology and phenology are based mainly on collections

from Thailand. DISTRIBUTION. — Laos (Xiangkhouang). Vietnam (Lam Dong?).

NE India, Myanmar, Thailand.

MATERIAL EXAMINED. — Laos. Xiangkhouang, Phu Bia, A.D.Kerr 2760 ( C).

DESCRIPTION

Stems cylindrical to narrowly fusiform, 20-40(50) cm long, 8-12 mm in diameter, of many nodes. Leaves narrowly ovate to lanceolate oblong, 5-10 cm long, 1.5-2.5 cm wide. Inflorescences 1-3, each with 1-3(5) flowers. Flowers odorless, widely opening, 6-9 cm across, white, disc yellow. Sepals narrowly triangular ovate, acute, 3-4 cm long, 1.2-1.6 cm wide. Petals broadly ovate, obovate, rhomboid or almost circular, narrowing to the base, round or shortly apiculate at apex, 4-5 cm long, 3.5-4 cm wide, 3-4 times wider than sepals; mentum narrowly conical., straight, 1.5-2 cm long, 4-6 mm in diameter. Lip pandurate, 3-lobed, as long as sepals, 3-3.5 cm wide; side lobes half circular, erect, embracing column; median lobe half circular to broadly oblong, emarginate, undulate and irregularly denticulate along margin; disc with flat broad fleshy keel splitting distally into 3-5 low lamellas. Column white, 6-8 mm tall ( Fig. 2E ).

REMARKS

Tentative records of this species for southern Vietnam may be based on introduced or naturalized plants. Some collections from the highlands of Lam Dong province of southern Vietnam (Bidoup mt.) identified in the past as D. infundibulum (Poilane 30726, 30900) belong to D. wattii .

Lindley (1858) concerning D. infundibulum wrote the following: “A very striking plant, intermediate between D. formosanum and longicornu , having the large flowers of the former and the slender habit and narrow leaves of the latter. The lip with large round lateral lobes also distinguishes it from the former and the large petals with a circular middle lobe to the lip and short funnel-shaped mentum from the latter”.

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.