Ceratostylis sessilis

Ceratostylis sessilis J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 2, 2 (1911) 7

Type: Kock, de IV

Rhizome branched. Stems fascicled, erect, in cross section elliptic, up to 11 cm long, 0.2 cm wide, apex 1-leaved, at the base covered with several tubular, up to 3.5 cm long scales, sometimes the young plants leafy at the base. Leaf sublinear, apex long conical-apiculate, at the base narrowed and conduplicate, convex above with a longitudinal groove, convex below, 3.5-4 cm long, 0.33-0.43 cm wide. Inflorescence fasciculate-small-capitate, peduncle thin, pilose, 1-flowered, 0.37 cm long. Floral bracts in the basal part tubular, split above, acute, thin membranous, about as long as the ovary. Flowers rather widely opening, 0.63 cm wide, 0.75 cm long. Sepals divergent, outside at the base sparsely pilose. Median sepal oblong, obtuse, apex somewhat concave and outside somewhat thickened, 3-nerved, about 0.5 cm long, 0.2 cm wide. Lateral sepals obliquely oblong, concave, apex narrowly obtuse and somewhat thickened outside, front margin inflexed, 3-nerved, 0.5 cm long, in total 0.57 cm long, above the base 0.2 cm wide; mentum short, bilobed, almost 0.07 cm long. Petals oblong-elliptic, narrowed towards the base, slightly spathulate, acute, convex, apex recurved, 1-nerved, 0.44 cm long, 0.15 cm wide. Lip sessile, small, 0.25 cm long, 0.14 cm wide, parallel with and appressed to the column, apex incurved, ovate, apical margin narrowly thickened, apex short triangular-thickened, obtuse, concave, basal half very minutely ciliolate, 3-nerved, inside in basal half with two parallel puberulous ribs, midrib thickened in apical part. Column bipartite, 0.13 cm long, arms subparallel, oblong, rounded, outside convex, inside concave. Anther cucullate, suborbicular, apex thickened, rounded, at the base bilobulate, 0.06 cm wide. Pollinia 8, clavate-pyriform. Column-foot almost absent. Ovary with pedicel pilose, 0.3 cm long. (After Smith, 1913)

Colours: Flower white.

Habitat: Epiphyte in upper montane forest. Altitude 2000 m.

Flowering time in the wild: January.

Distribution: Malesia (New Guinea, endemic).

Distribution in New Guinea: Papua (Indonesia). See map: 125-136M.JPG

Cultivation: Cool growing epiphyte.