Orchids of New Guinea

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Octarrhena lorentzii

Octarrhena lorentzii J.J.Sm., Bull. Dép. Agric. Indes Néerl. 39 (1910) 18

Type: Römer, von 1338 (holo BO; iso L)

Synonyms:

Phreatia lorentzii (J.J.Sm.) Kraenzl. in Engl., Pflanzenr. IV. 50. II. B. 23 (1911) 11
Chitonanthera lorentzii (J.J.Sm.) J.J.Sm., Nova Guinea 14 (1929) 483
Chitonanthera suborbicularis J.J.Sm., Nova Guinea 14 (1929) 485, pl. 80, fig. 126
- Type: Lam 1607 (holo L; iso BO)
Octarrhena suborbicularis (J.J.Sm.) P.Royen, Alp. Fl. New Guinea 2 (1979) 757, fig. 262

Terrestrial. Stem unbranched, erect, straight, thin, 10 cm long, leafy, rooting, internodes 0.5-0.8 cm long, upper roots appressed to the stem. Leaves distant, erect, thin-textured, laterally compressed, linear-subulate, obtuse, 1.3-1.5 cm long, when dried 0.08-0.1 cm wide; sheaths tubular, much surpassing the internodes. Inflorescences axillary, erect, elongated, laxly many-flowered; peduncle thin, 8-9 cm long, with 2 tubular scales; rachis curved, band-like, broadly unequally winged-dilated, ensiform, glabrous, 2.5-4 cm long, to 0.24 cm wide, internodes curved, 0.3-0.5 cm long. Floral bracts distichous, widely patent, triangular, acutely acuminate, concave, strongly keeled, 0.24 cm long. Flowers widely opening, 0.5 cm wide, the lateral sepals and the median sepal shortly connate. Median sepal broadly ovate, obtuse, convex, 1-nerved, 0.25 cm long and wide. Lateral sepals a little smaller than the dorsal sepal, obliquely ovate, slightly acuminate, subacute, convex, 1-nerved, 0.2 cm long and wide. Petals free, very small, nearly semiorbicular, very shortly acuminate, the very tip broadly obtuse, convex, dorsally concave, puberulous, 0.06 cm long, 0.08-0.1 cm wide. Lip horizontal, entire, rounded-5-angled, broadly obtuse, at the base truncate, minutely puberulous, 1-nerved, 0.16 by 0.17 cm. Column short, 0.13 cm long, broad, ventrally strongly ventricose-convex, wings rather large, triangular, incurved, concave, puberulous, clasping the anther; rostellum triangular; stigma transverse. Anther flat, subreniform, lobulate, 0.05 cm wide, initially 3-lobed. Pollinia 8, unequal, obliquely pear-shaped, triangular and subelliptic. Ovary triangular, 6-grooved, glabrous.
(After Smith, 1911)

Colours:

Flowers orange.

Habitat:

Terrestrial in open subalpine vegetation, also epiphytic in moss cushions; 3000 to 3850 m.

Distribution:

Malesia (New Guinea, endemic).

Distribution New Guinea:

Papua (Indonesia); Papua New Guinea. See map

Cultivation:

Cool growing terrestrial, requires light position.

Flowering time in the wild:

February, March, April, May, July, August, September, October, November.

References:

Smith, J.J., Nova Guinea 8, 3 (1911) 597, t. 108A
Smith, J.J., Nova Guinea 12, 1 (1913) 95
Smith, J.J., Nova Guinea 12, 4 (1916) 441
Smith, J.J., Nova Guinea 14, 3 (1929) 484, as Chitonanthera lorentzii (J.J.Sm.) J.J.Sm.
Royen, P. van, Alp. Fl. New Guinea 2 (1979) 751, fig. 260, pl. 91
Royen, P. van, Alp. Fl. New Guinea 2 (1979) 757, fig. 262, as Octarrhena suborbicularis (J.J.Sm.) P.Royen

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Podochileae
Subtribe Thelasiinae
Genus Octarrhena
Species Octarrhena lorentzii

Notes:

Interesting because of the flattened rachis of the inflorescence, which is even more extremely developed in Octarrhena platyrhachis.