Orchids of New Guinea

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Dendrochilum longifolium

Dendrochilum longifolium Rchb.f., Bonplandia 4 (1856) 329

Type: Stange cult. (Schiller) s.n., herb. Reichenbach f. 4908 (holo W)

Synonyms:

Platyclinis longifolia (Rchb.f.) Hemsl., Gard. Chron. (1881, II) 656
Acoridium longifolium (Rchb.f.) Rolfe, Orchid Rev. 12 (1904) 220
Dendrochilum bracteosum Rchb.f. in Walp., Ann. Bot. Syst. 6 (1861) 241
- Type: Finlayson s.n. (holo K)
Acoridium bracteosum (Rchb.f.) Rolfe, Orchid Rev. 12 (1904) 220
Dendrochilum amboinense J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 3, 1 (1919) 95 (nom. nud.)
- Type: Bogor cult. II M a 35 (holo BO ; iso K, L, SING)
Dendrochilum clemensiae Ames, Orchidaceae 2 (1908) 109, fig.
- Type: Clemens 642 (holo PNH, lost; photograph at AMES)
Dendrochilum fuscum Teijsm. & Binn., Natuurk. Tijdschr. Ned.-Indië 24 (1862) 305
- Type: Bogor cult. (Lobb) s.n. (holo BO?, lost?; iso SING [Hort. Bot. Bog. 57])
Dendrochilum longifolium Rchb.f. var. buruense J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 3, 9 (1928) 451
- Type: Stresemann 337 (Moluccas, Buru, Mt. Togha) (holo L)
Dendrochilum longifolium Rchb.f. var. fuscum J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 3, 1 (1919) 96 (nom. nud.)
- Type: Bogor cult. II M b 20 (holo BO?)
Dendrochilum longifolium Rchb.f. var. papuanum J.J.Sm., Nova Guinea 8, 3 (1911) 527
- Type: Bogor cult. (Djibdja) 112 (holo BO)
Dendrochilum murrayi R.S.Rogers & C.T.White, Trans. & Proc. Roy. Soc. South Australia 44 (1920) 114, pl. 7
- Type: White 606 (BRI)
Platyclinis bartonii Ridl., J. Straits Branch Roy. Asiat. Soc. 50 (1908) 128
- Type: Barton 5 (holo K)
Dendrochilum bartonii (Ridl.) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1911) 106
Platyclinis longifolia (Rchb.f.) Hemsl. f. papuana Ridl., Trans. Linn. Soc. London, Bot. 9 (1916) 202
- Type: Rothschild cult. (Wollaston) s.n. (not located)

Roots 0.15 cm diam., glabrous, not or sparsely branching. Rhizome short. Pseudobulbs 0.3-0.5 cm apart, cylindrical, fusiform to ovoid, 3-8.5 by 0.6-1.8 cm, initially covered with 4-6 nearly perfectly tubular, rounded to acute cataphylls which soon disintegrate into persistent fibres. Leaf petiolate; petiole channelled, 1.5-7 cm long; blade lanceolate, acute, 8-25 by 2.4-5 cm , thin-textured with 7-9 distinct (and many indistinct) nerves. Inflorescence synanthous, suberect, peduncle slender, terete, 11.5-24.0 cm long, (sub)glabrous; rachis more or less pendent with distichously alternating flowers, moderately dense, 40-50-flowered with internodes of c. 0.30 cm, somewhat furrowed, c. 14 cm long, (sub)glabrous, basally with 1-5 appressed, non-floriferous bract(s). Floral bracts (semi-orbicular-)ovate to broadly oblong when spread, persistent, acuminate, 0.42-0.8 by 0.4-0.49 cm, quite entire, 9-10-nerved, sparsely and finely setose. Flowering starting from the basal part of the rachis. Flower widely opening, c. 0.8 cm across. Median sepal (oblong-)lanceolate, acuminate, 0.66-0.79 by 0.21-0.26 cm, quite entire, 3-veined, glabrous; lateral sepals lanceolate, usually widest in the proximal part, acuminate, 0.63-0.82 by 0.21-0.28 cm, quite entire, 3-veined, glabrous; petals obliquely lanceolate, acuminate to subacute, 0.58-0.69 by 0.19-0.23 cm , quite entire to very slightly irregular along the margin, 3-veined, glabrous. Lip rather mobile, more or less pendent, sessile, 3-lobed, 0.45-0.67 by 0.27-0.39 cm, 3-veined, glabrous and smooth, with two proximally interconnected keels running from the base to near the middle of the mid-lobe, between the keels with a longitudinal groove extending almost to the lip-apex; margin slightly irregular along the mid-lobe, otherwise quite entire; disc flat; side lobes porrect to slightly spreading, obliquely linear-triangular, acute to acuminate, distinctly shorter than the mid-lobe; mid-lobe gradually recurved, broadly (orbicular-)elliptic to obovate, acuminate. Column suberect, strongly incurved, semiterete, 0.29-0.4 cm long, smooth, at the apex prolonged into a rounded, finely (dentate-)crenate wing which distinctly exceeds the anther; foot short; stelidia appearing from the middle of the column proper, suberect to more or less porrect, linear(-triangular), somewhat falcate, unequally emarginate to very obliquely acuminate, distinctly shorter than the column proper (approximately reaching the level of the anther), smooth. Anther ovate-triangular to reniform in upper view, acute to acuminate in front, with a distinct, conical wart on top. Pollinia obliquely (ellipsoid-)pyriform with short caudicles. Rostellum somewhat protruding, ovate-triangular; fertile stigma obtriangular semi-orbicular to subquadrate in outline, concave with slightly elevated margins. Ovary with pedicel semifusiform-conical to nearly terete, not twisted, 0.31-0.52 cm long, (sub-)glabrous. Fruit not seen.
(After Pedersen, 1997, and O, 1994).

Colours:

Pseudobulbs green to orange, the latter especially when growing in exposed positions. Sepals and petals translucent green to greenish yellow. Lip yellow, green or brownish, usually with a brown mid-lobe, the keels and often the central groove bright green.

Habitat:

Epiphyte in lowland to montane forest in shaded to exposed positions (upper altitudinal limit dubious). Altitude 250-3000 m.

Distribution:

Malesia (Peninsular Malaysia, Singapore, Sumatra, Java, Borneo, ?Sulawesi, ?Lesser Sunda Islands, Moluccas, New Guinea, The Philippines), Burma.

Distribution New Guinea:

Papua (Indonesia); Papua New Guinea. See map

Cultivation:

Warm to cool growing epiphyte.

Flowering time in the wild:

January, February, March, April, May, June, July, September, October, December.

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Arethuseae
Subtribe Coelogyninae
Genus Dendrochilum
Section Platyclinis
Species Dendrochilum longifolium

Literature:

Smith, J.J., Orchid. Java (1905) 166
Smith, J.J., Orchid. Java, Fig.-Atl. (1909) fig. 125
Smith, J.J., Nova Guinea 12, 1 (1913) 11, as Dendrochilum longifolium Rchb.f. var. papuanum J.J.Sm.
Smith, J.J., Nova Guinea 12, 3 (1915) 196, as Dendrochilum longifolium Rchb.f. var. papuanum J.J.Sm.
Schlechter, R., Repert. Spec. Nov. Regni Veg. Beih. 21 (1923) t. 41, fig. 141, as Dendrochilum bartonii (Ridl.) Schltr.
O'Byrne, P., Lowland Orchid. Papua New Guinea (1994) 80, fig.
Pedersen, H. AE., Opera Bot. (1997) 131, pl. VB, fig. 90

Notes:

Dendrochilum longifolium Rchb.f. is one of the most commonly encountered orchids in New Guinea. It is noteworthy that the genus Dendrochilum, so rich in species in Sumatra, Borneo and the Philippines, is represented in New Guinea by just one species, which is not even endemic but is one of the most common orchids on the island..