Thelasis mamberamensis

Thelasis mamberamensis J.J.Sm., Meded. Rijks-Herb. 23 (1915) 18

Type: Janowsky 466 (holo BO; iso L)

Stem short, with long continued growth at the apex, at the base densely rooting, with c. 5 leaves present simultaneously, to 2.5 cm long, in the basal part covered with the persistent overlapping leaf-sheaths. Leaves closely spaced, distichous, erect-patent, divergent, articulated, linear, acutely channelled, unequally obtusely bilobulate with a minute obtuse apicule between the lobules, fleshy, 7.5-15 by 0.8 cm (when flattened); sheaths overlapping, tubular, in front almost along their entire length torn open and irregularly submembranous-margined, at the apex conduplicate-channelled, persistent, 2-2.4 cm long. Inflorescences axillary, erect, densely many-flowered, equalling or surpassing the leaves; peduncle subterete, slightly flattened, 13-15.5 cm long; peduncle-scales c. 4, tubular, acute, keeled, to 0.7 cm long; rachis nodding, angular. Floral bracts persistent, widely patent, incurved, at the base dilated-triangular, gradually acuminate, concave, to almost 0.2 cm long. Flowers turned to all sides, inserted on thickenings of the rachis, very small, somewhat fleshy, 0.33 cm long. Sepals cohering. Median sepal ovate, in apical 2/5 slightly contracted, obtuse, somewhat concave, 1-nerved, 0.33 by 0.18 cm. Lateral sepals obliquely triangular, acuminate, narrowly obtuse, concave, 1-nerved, with the nerve dorsally prominent, 0.33 by almost 0.2 cm. Petals parallel to the sepals, at the apex recurved, oblong-ovate, distally narrowed, obtuse, at the base clawed-contracted, somewhat concave, 1-nerved, 0.23 by 0.1 cm. Lip at the base thick, porrect, at the apex recurved, concave, clawed, underneath in the basal part conspicuously grooved, when flattened almost 0.3 cm long; claw cuneate-semi-elliptic, with a strong longitudinal, convex thickening, on either side delimited by a narrow concavity, 0.1 cm long, at the apex 0.1 cm wide; blade in outline subovate-triangular, indistinctly 3-lobed, with irregular margins, channelled in the middle, on either side of the channel slightly convex, 3-nerved, almost 0.2 cm long, 0.23 cm wide; lateral lobes erect, angular-semiorbicular; mid-lobe much larger, triangular, obtuse, slightly over 0.1 cm long. Column 0.2 cm long, dorsally convex, in front with raised margins, concave; clinandrium deeply concave, at the apex truncate, denticulate, with a larger tooth on either side, column-foot very indistinct; rostellum continuing the line of the column, porrect, elongated, above concave, convex below, narrowly bidentate; stigma transversely elliptic. Anther cucullate, triangular, gradually long acuminate, with narrowly obtuse tip, at the base truncate, 0.15 cm long; pollinia 8, flattened, orbicular to orbicular-triangular; stipe linear, elongated. Ovary obconical, 3- or almost 6-angular, 0.15 cm long; pedicel thinner, 0.25 cm long. (After Smith, 1916)

Colours: Flowers yellow.

Habitat: Epiphyte in lowland forest; 0 m.

Flowering time in the wild: September.

Distribution: Malesia (New Guinea).

Distribution in New Guinea: Papua (Indonesia). See map: 686-31M.JPG.