Dendrobium nebularum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 540; 21 (1923) t. 183, fig. 684.
Type: Schlechter 18752 (holo B, lost).
Erect tufted epiphyte, 8-20(-30) cm high, usually with ascending habit of growth. Roots 0.5-1.5 mm diameter. Rhizome short. Pseudobulbs 1.5-15(-20) by 0.3-1.6 cm; very variable in shape, slender cylindrical-fusiform to obclavate (sometimes quite swollen at the base as in Reeve 538, see fig. 27A), apex 1-3(-4)-leaved. Leaves 1.5-14 by 0.3-2.3 cm, subpetiolate, linear-lanceolate to elliptic, apex subacute, often mucronate; sheaths slightly ribbed, persistent. Inflorescences arising from the upper nodes of both leafless and leafy stems, 2-5-flowered, subsessile; bracts ovate to suborbicular, apiculate to shortly acuminate. Flowers 2-3.2 cm long, not widely opening long lasting. Median sepal 8-15 by 3-5 mm, ovate to ovate-lanceolate, acute to acuminate. Lateral sepals 19-31 by 4-7 mm, somewhat oblique, ovate-lanceolate, acuminate; basal fused part 5-l0 mm long, conical; mentum total length 11-19 mm tip incurved, subacute to obtuse, bilobed. Petals 7-13 by 2-4 mm, narrowly oblong to subrhombic, acute to subacuminate. Lip 17-26 by 3-3.5 mm (expanded width to 5 mm subtrilobate, linear-oblanceolate, adnate to column foot at base, margins of free part incurved, apex triangular to acuminate, margins erose. Column 3-3.5 mm long; foot 11-19 mm long; anther 2-2.5 mm broad; pollinia c. 1.5 mm long. Ovary 5-winged, usually with smaller 6th wing on ventral surface, wings undulate, sometimes very markedly; pedicel and ovary 16-30 mm long. Fruit 28 by 14 mm, ovoid.
(after Reeve & Woods, 1989).
Colours: Roots white with orange tips. Leaves pale green usually striated purplish red. Flowers greenish white to yellow (veins sometimes purple-red) or dark red to purplish red, lip apex rarely coloured differently.
Habitat: Epiphyte, commonly in montane Nothofagus forests; rarely terrestrial, 1400-2800 m.
Flowering time in the wild: February-May, July, October.
Distribution: Moluccas (Seram), New Guinea.
Distribution in New Guinea: Papua New Guinea (East Sepik, Enga, Southern Highlands, Western Highlands, Madang and Morobe Provinces).
Map: NEBULMAP.JPG [Dendrobium nebularum Schltr., distribution map, redrawn from T.M. Reeve & P.J.B. Woods, Notes Roy. Bot. Gard. Edinburgh 46 (1989) 289, map 16.]
Notes: Dendrobium nebularum is a widely distributed species but it is not common. In any one locality often only a single plant is found and therefore herbarium material is scanty.
Dendrobium nebularum is most closely allied to Dendrobium pentapterum and it is sometimes difficult to distinguish dried specimens. Dendrobium nebularum may be recognised by its orange root tips, the striated sheaths and bracts, the usually longer stems and subpetiolate leaves (not always seen on young plants), the 2-5 (not single)flowered inflorescences with the flowers not opening widely, the narrower lateral sepals, the margins of the lip being incurved for most of its length, the different colour of the flowers (lip apex not bright orange) and the more widely undulate wings on the ovary. This species is one of the few 'Oxyglossum' orchids with orange root tips, a feature noted with several New Guinea montane dendrobiums which are commonly epiphytic on Nothofagus (Southern Beech) trees. Dendrobium nebularum was probably named by Schlechter to commemorate the misty and cloudy mountain habitat in which these miniature orchids thrive.
The flowers of this species are not widely opening so horticulturally it is not very noteworthy. The purplish red forms are usually more attractive than the pale greenish white to yellow colour forms.
(after Reeve & Woods, 1989).
Cultivation: Cool growing epiphyte.