Dendrobium juncoideum P.Royen, Alp. Fl. New Guinea 2 (1979) 430, fig. 149.
Type: Paymans 654 (holo CANB).
Tall, much branched, caespitose, erect, up to 70 cm high, epiphytic herb. Stems glabrous, very slender, many-noded. Leaves patent, linear-lanceolate, 2-4 by 0.3 cm, subcoriaceous, glabrous, coarsely scarious-serrulate along margin, acute by the extended midrib, midrib grooved above, prominent below, lateral nerves many, 2 or 3 on either side of midrib stronger developed than the rest, more prominent below than above, margins membranous; sheaths 6-13 mm long, many-ribbed, glabrous. Inflorescence 3-5-flowered, up to 8 mm long. Peduncle glabrous, 1-3 mm long. Bracts glabrous, broadly ovate-orbicular, 3 by 5 mm, acutish, midrib crested. Rachis glabrous, slightly flexuose, 5 mm long. Bracteoles glabrous, widely ovate, 4-8 mm long, acuminate, 5-7-nerved, midrib hardly crested. Pedicels glabrous, 12 mm long, 3-sided. Ovary glabrous, claviform, slightly curved, 15 by 2 mm, 5-ribbed, all ribs rounded. Median sepal glabrous, elliptic, 13 by 6 mm, rounded and subcrenulate at tip, 5-nerved. Lateral sepals glabrous, obliquely ovate, 32 by 8 mm, free apical part ovate, 12 by 8 mm, acute, 7-nerved, midrib crested on outside and slightly grooved on inside at tip, spur 7 mm long, cuspidate at tip. Lateral petals indistinctly scattered papillate along apical margin only, broadly spathulate, 12 by 6 mm, rounded, 3-nerved at base, up to 5-nerved in apical part, midrib slightly crested on outside at tip only. Lip glabrous, narrowly oblong-spathulate, 25-30 by 6-8 mm, slightly 3-lobed at tip, median lobe broadly ovate-triangular, minutely apiculate, lateral lobes rounded, margin of all lobes finely scarious-serrulate, entire lip 5-nerved in basal part, 9-nerved in apical part. Column short and stout, 6 by 4 by 2 mm. Stelidia triangular-rounded, apiculate. Anther cucullate, 3 by 4 by 2.5 mm, truncate and appressed fimbriate at tip, retuse and 2-humped at base. Pollinia trapezoid-5-sided. Column-foot 22 mm long, slightly curved, flat on inside.
(after van Royen, 1979).
Colours: Flowers purple.
Habitat: Epiphyte in subalpine shrubberies. Altitude 3000 to 3100 m.
Flowering time in the wild: July to August.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Central and Eastern Highlands Province).
Notes: Closely related to Dendrobium crenatifolium.
Cultivation: Cool growing epiphyte.