Dendrobium grossum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 584; 21 (1928) t. 195, fig. 732.
Type: Schlechter 18498 (B, lost); 19073 (B, lost; AD, AMES, BM, BO, G, K, L 2x, NSW, S).
Rhizome very short, roots elongated, filiform, flexuose, glabrous. Stems crowded, erect, slender, straight, erect, terete, up to 80 cm by 0.8 mm, many-leaved. Leaf sheaths entirely covering the stem, sparsely rugulose. Leaves erect-patent, lanceolate, 8-12 by 1.7-3 cm, apex obtuse, unequally bilobulate, shining on upper side. Inflorescences lateral from the stem, peduncle almost absent, 2-flowered, spathe short, obtuse. Pedicel and ovary 0.8 cm long, glabrous. Flowers c. 4.5 cm across. Dorsal sepal oblong, 2.4 cm long, apex obtuse. Lateral sepals obliquely oblong, slightly widened at the base, 2.4 cm long, apex obtuse; mentum 0.3 cm long, obtuse. Petals obliquely oblong-elliptic, c. 2.4 cm long, apex obtuse; broader than the sepals, more thin-textured. Lip 3-lobed in the middle, 1 cm long, rounded at the base, sparsely covered with tooth-like papillae, with a linear acute basal keel expending to the middle of the midlobe, at the base on either side with a very short crest; lateral lobes erect, triangular, obtuse; midlobe much larger than the lateral lobes, subquadrate-rounded, apiculate. Column short, thick, clinandrium 3-lobulate, the lateral lobules short, truncate, the median very low; column-foot 0.3 cm long, at the apex with a cavity. Anther rounded-cucullate, glabrous.
(after Schlechter, 1912).
Colours: Sepals and petals light yellow or orange-yellow, lip reddish with a red keel.
Habitat: Epiphyte in montane forest. Altitude 1000-1800 m.
Flowering time in the wild: January, February, July, October.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Enga, Madang, and Eastern Highlands Provinces).
Map: GROSSMAP.JPG [Dendrobium grossum Schltr., distribution map.]
Cultivation: Intermediate growing epiphyte.