Dendrobium longissimum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 586; 21 (1928) t. 196, fig. 735.
Type: Schlechter 19878 (holo B, lost; iso L (missing), S).
Rhizome very short, roots elongated, filiform, flexuose, glabrous. Stems crowded, pendulous, terete, up to 200 cm by 10 mm, many-leaved, unbranched. Leaf sheaths entirely covering the stem. Leaves narrowly lanceolate, 18-22 by 1.8-2.2 cm, apex acute. Inflorescences lateral from the stem, hardly developed, 2-flowered, spathe laterally compressed, semiorbicular, broadly obtuse. Ovary 0.5 cm long, subsessile, cylindrical, glabrous. Flowers c. 2.5 cm across, fleshy, strongly fragrant. Dorsal sepal oblong, 1.6 cm long, apex obtuse; incurved, thickened to the apex. Lateral sepals obliquely oblong, widened at the base, 1.6 cm long, apex obtuse; mentum short, obtuse. Petals obliquely oblong, similar to the sepals but a little shorter, apex obtuse. Lip 3-lobed in the middle, 0.8 by 0.5 cm, in basal half inside transversely rugulose, with a verrucose basal keel extending to the base of the midlobe; lateral lobes small, ovate-triangular, obtuse; midlobe large, elliptic, subacute. Column short, rather thick, clinandrium 3-lobulate, the lobules rounded-obtuse; column-foot incurved, thickened at the apex; anther quadrangular-cucullate, glabrous.
(after Schlechter, 1912).
Colours: Flower creamy yellow, the lip with an orange-yellow keel, the lateral lobes with brown margins and veins.
Habitat: Epiphyte on tall trees in lower montane forest. Altitude 1200 m.
Flowering time in the wild: June.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Morobe Province: Maboro Mountains).
Map: LONGIMAP.JPG [Dendrobium longissimum Schltr., distribution map.]
Cultivation: Intermediate growing epiphyte.