Dendrobium polyschistum

Dendrobium polyschistum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 575; 21 (1923) t. 192, fig. 720.

Type: Schlechter 20279 (holo B, lost; iso AMES, BO, E, G, K, L, NSW).

Rhizome very short, roots elongated, filiform, flexuose, glabrous. Stems crowded, erect to patent, slender, 30 to 40 cm by 1.5 mm, many-leaved, not or sparsely branched, entirely covered by the leaf sheaths. Leaves narrowly linear, 5-7 by 0.15-0.25 cm, apex acute. Inflorescences laterally from the stem, short, 2-flowered; spathe laterally compressed, narrowly oblong. Floral bracts minute. Pedicel and ovary 0.9 cm long, subclavate, glabrous. Flowers c. 6 cm across. Dorsal sepal narrowly lanceolate, 3 cm long, apex elongated-acuminate. Lateral sepals obliquely narrowly lanceolate, lobe-like widened at the base, 3 cm long, apex elongated-acuminate; mentum oblongoid, 0.5 cm long, obtuse. Petals obliquely linear, a little shorter than the sepals, apex elongated-acuminate. Lip 3-lobed below the middle, curved, 1.1 cm long, cuneate at the base, with a median keel extending from the base to the middle which in front is split into narrow lobes, in the basal half with scattered short toothed crests, on the midlobe with many not very closely set subulate papillae; lateral lobes obliquely lanceolate, c. 0.3 cm long, acute; midlobe very broadly rhombic, 0.7 by 1 cm, at the base claw-like narrowed, margins deeply lacerate-fimbriate, apex short-acuminate. Column short, clinandrium 3-lobulate, the lateral lobules obliquely rhombic, serrulate, the median short, tooth-like; column-foot 0.5 cm long, below the apex with 2 elliptic swellings. Anther broadly quadrate, in front truncate and papillose.
(after Schlechter, 1912).

Colours: Flowers white, outside slightly flushed reddish.

Habitat: Epiphyte in lower montane forest. Altitude 1000 to 1800 m.

Flowering time in the wild: February, September.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua New Guinea (Sandaun and Enga Provinces).

Map: POLSCMAP.JPG [Dendrobium polyschistum Schltr., distribution map.]

Cultivation: Intermediate growing epiphyte.


Two varieties have been described, of which the status is at present unclear:

Dendrobium polyschistum Schltr. var. graminiforme Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 576.

Type: Schlechter 16682 (holo B, lost).

Differs from var. polyschistum by the more slender, grass-like habit, by the club-shaped fringes of the lip, by the central high keel with a single crest on either side, and by the large reniform midlobe.

Colours: Flower whitish.

Habitat: Epiphyte in lower montane forest. Altitude 1000 to 1500 m.

Flowering time in the wild: October.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Nabire Regency); Papua New Guinea (Madang Province: Kani Mountains).

Cultivation: Intermediate growing epiphyte.


Dendrobium polyschistum Schltr. var. marginatum J.J.Sm., Nova Guinea 14 (1929) 411, pl. 62, fig. 63.

Type: Lam 1499 (holo L; iso BO).

Stems 20 cm long, internodes to 2.8 cm long. Leaf sheaths with thin raised lines, minutely verruculose-punctate, at the apex with a conspicuous triangular acute tooth opposite the leaf-blade. Leaves linear, 7.5 by 4 cm, thin coriaceous, apex unequally obtusely bidentate. Inflorescences laterally from the stems; peduncle 0.4 cm long, 2-flowered, spathe 0.4 cm long. Pedicel and ovary 1.1 cm long. Flowers c. 3.5 cm across. Dorsal sepal 2 cm by 3.6 mm. Lateral sepals 2 cm by 5.8 mm, mentum c. 0.45 cm long. Petals 1.95 cm by 1.3 mm. Lip 3-lobed, when flattened 0.83 by 0.38 cm. Column 0.33 cm long; column-foot 0.45 cm long, with a cavity near the apex.
(after Smith, 1929).

Colours: Sepals and petals dirty reddish pink tinged green and violet, lip pale yellow with a light yellow apex, the lateral lobes with thin violet margins, column greenish yellow with a violet apex, the foot violet with a yellow apex, ovary dirty reddish pink.

Habitat: Epiphyte in lower montane forest. Altitude 1400 m.

Flowering time in the wild: October.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Jaya Wijaya Regency).

Cultivation: Intermediate growing epiphyte.