Dendrobium vesiculosum

Dendrobium vesiculosum M.A.Clem. & D.L.Jones, Lasianthera 1 (1996) 9, fig. 2, pl. 3 & 4A.

Type: Canberra Nat. Bot. Garden cult., 2 Jul. 1990 (Clements 6631) (holo CANB, iso CANB, NCBG).

Plant epiphytic with pendulous stems. Rhizome much abbreviated. Pseudobulbs 25-35 cm by 0.8-1.2 cm, more or less cylindrical, when young covered with hyaline sheaths. Leaves c. 8 per pseudobulb, linear-elliptical to linear-lanceolate, 8-10 by 1.8-2.2 cm, thin-textured; base cuneate; apex acuminate and slightly recurved. Inflorescence lateral, bearing 2 flowers. Peduncles 0.7-1 cm long, sheathed with papery, hyaline sterile bracts. Pedicels about 1 cm long, slender. Ovary c. 3 mm long. Flowers c. 2 cm across, expanding widely, lacking any noticeable scent, not self-pollinating. Dorsal sepal linear-ovate, 1.4-1.5 cm by 4.5-5 mm, erect and shallowly recurved; apex subacute. Lateral sepals linear-oblong, 1.4-1.5 cm by 4.5-5 mm, slightly falcate, connate at the base, widely divergent; apex subacute. Petals lanceolate, 1.2-1.4 cm by 4-4.5 mm, widely divergent; apex subacute. Lip linear-lanceolate, 1.2-1.3 cm by 4.5-5 mm, thin textured, erect in basal third then porrect; apex acute to acuminate, decurved; callus linear-lanceolate, slightly thickened, with minute whitish vescicles in the apical half. Column c. 4 mm long, porrect from the end of the ovary; column foot c. 5 mm long, slightly curved. Anther c. 2 mm by 1.5 mm, erect, with small projections. Pollinia 4, c. 1 mm long, linear-clavoid, waxy. Stigma c. 1.2 mm long, elliptical, sunken. Fruit not seen.
(after Clements & Jones, 1996).

Colours: Leaves bright green. Flowers pale greenish yellow, callus on the lip yellowish green with minute whitish vescicles. Anther pale yellow, pollinia orange.

Habitat: Epiphyte on trees in disturbed rainforest on low ridges in the valley floor. Altitude 500 m.

Flowering time in the wild: Cultivated specimens flowering throughout the year. Flowers last 5-10 days.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua New Guinea (Morobe Province).

Map: VESICMAP.JPG [Dendrobium vesiculosum M.A.Clem. & D.L.Jones, distribution map.]

Notes: Dendrobium vesiculosum is related to Dendrobium anosmum, but may be distinguished by the much smaller, greenish yellow flowers.

Cultivation: Warm growing epiphyte.