Octarrhena platyrhachis

Octarrhena platyrhachis P.Royen, Alp. Fl. New Guinea 2 (1979) 720, fig. 247

Type: Pullen 370 (holo CANB; iso L)

Epiphytic or terrestrial, erect, 13-35 cm high. Stems glabrous, unbranched or sparsely branched, slightly flexuose, subterete, leafy in apical part only. Leaves erect-patent, herbaceous, glabrous, ensiform-linear, 0.9-4 by 0.5-0.3 cm, acute, slightly narrowed at the base; sheaths glabrous, 0.5-1.8 cm long, obliquely widened and truncate at tip, compressed, 3- to 6-ribbed. Inflorescences 6.5-14 cm long, many-flowered [wrongly stated to be 2- to 5-flowered by van Royen]. Peduncle glabrous, slender, 3-5.6 cm long, with 1-3 scales along entire length. Floral bracts glabrous, tubular in basal half, ligulate in upper half, 0.3-0.5 cm long, acute. Rachis glabrous, up to 12 cm long, strongly flexuose, laterally compressed and much widened, up to 1.2 cm wide. Flowers sessile. Sepals patent, connate at base. Median sepal glabrous, broadly ovate, 0.25-0.3 by 0.3-0.33 cm, obtusely acuminate, 1-nerved. Lateral sepals glabrous, obliquely ovate, 0.2-0.25 by 0.25-0.3 cm, obtuse or subacute, otherwise similar to median sepal. Petals densely pilose, reniform, 1-1.5 by 0.3-0.5 mm. Lip densely pilose on upper side, with slightly longer hairs along the margins, glabrous on underside, quadrangular-elliptic, 0.25-0.3 by 0.25-0.3 cm, obtuse. Column short and stout, 0.1-0.15 by 0.1-0.15 cm, inflated in lower part. Stelidia 2, curved, oblong, 0.4-0.7 mm long, pilose, but along narrow margin with longer hairs. Anther sagittate-cupuliform, 0.6 by 0.7 by 0.2 mm. Pollinia 8, unequal, ellipsoid-bean-shaped, 0.2-0.3 mm long. Ovary glabrous, clavate, 0.25-0.3 cm long. Fruit not seen. (After van Royen, 1979)

Colours: Rachis and flowers orange, the flowers darker so.

Habitat: Epiphyte in upper montane forest, growing between moss in shaded positions, also terrestrial along tracks; 2370 to 3300 m.

Flowering time in the wild: March, May, June, August.

Distribution: Malesia (New Guinea, endemic).

Distribution in New Guinea: Papua New Guinea. See map: 486-44M.JPG.

Cultivation: Cool growing epiphyte, requires shaded position.

Notes: Somewhat similar to Octarrhena lorentzii, but with an even more strongly flattened and broader rachis of the inflorescence.