Cadetia quinquecostata (J.J.Sm.) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 424.
Basionym: Dendrobium rumphiae Rchb.f. var. quinquecostatum.
Rhizome short. Stems crowded, erect, slender, widened in upper part, 4-angled, 3.5-10 cm long, at apex 2.7-3.5 mm diameter, 1-leaved. Leaves erect, lanceolate, falcate, 4.5-8 by 0.7-0.95 cm, carnose, base rounded, apex bidentate. Inflorescences terminal from the leaf axil, arising in succession, 1-flowered; spathe 0.75-1.25 cm long. Pedicel 0.7 cm long; ovary 0.3 cm long, triangular in cross section, laterally ribbed. Flower resupinated, c. 0.9 cm across. Dorsal sepal oblong-ovate, 0.45 cm by 2.3 mm, lower margins strongly recurved, apex obtuse, apiculate. Lateral sepals obliquely subovate, free part 0.5 cm by 2.7 mm, apex obtuse, subapiculate; mentum spur-like, more or less clavate, 0.5 cm long, obtuse. Petals reflexed, obliquely linear-lanceolate, 0.45 cm long, at base 1.8, in the middle 1 mm wide, apex obtuse. Lip clawed, 3-lobed in basal third of the blade, 0.46 by 0.43 cm; lateral lobes erect, obliquely quadrangular, concave, in front minutely erose, obtuse; midlobe broadly cuneate-subquadrate, 0.3 by 0.35 cm, with 5 swollen keels, pubescent at the base, margins swollen, apex truncate, retuse, with a small rounded apicule. Column 0.18 cm long, stelidia triangular, obtuse, longer than the triangular filament; column-foot pubescent at the base.
(after Smith, 1909).
Colours: Flower white, lip with rose markings.
Habitat: Epiphyte in lowland rainforest. Altitude 0-175 m.
Flowering time in the wild: February, July, August.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Puncak Jaya, Merauke, and Jayapura Regencies).
Map: QUICOMAP.JPG [Cadetia quinquecostata (J.J.Sm.) Schltr., distribution map.]
Notes: Cadetia quinquecostata is very similar to Cadetia collina, and should probably be considered a form or subspecies of the latter. It differs mainly in the narrower and longer leaves, these being 1.8 to 2.5 cm wide in C. collina, 0.7 to c. 1 cm wide in C. quinquecostata. Cadetia stenocentrum is also very closely related, differing apparently in that the lip has three instead of 5 keels on the midlobe, while the leaves are intermediate between C. collina and C. quinquecostata.
Cultivation: Warm growing epiphyte.