Diplocaulobium (Rchb.f.) Kraenzl.,
in Engl., Pflanzenr. IV. 50. II. B. 21 (1910) 331.
Sympodial epiphytic plants. Pseudobulbs present, consisting of one internode, one-leaved. Leaves without sheathing base, glabrous, dorso-ventrally flattened, articulate, duplicate, leathery. Inflorescence terminal, carrying a single flower. Flowers medium-sized to large, resupinate, predominantly white, but also various other colours, ephemeral. Sepals free. Petals usually similar to the dorsal sepal, but sometimes quite different. Lip without spur, not mobile. Column-foot present. Pollinia 4, solid-waxy, caudicles absent, stipe absent, viscidium absent.
Malaysia, Singapore, Brunei, the Philippines, Indonesia, Papua New Guinea, Australia, Solomon islands, east to Samoa. About 70 species; in New Guinea 50 species.
Epiphytes in lowland and montane forest, predominantly below 2000 m.
Diplocaulobium is a fairly uniform genus with one-leaved, often bottle shaped pseudobulbs carrying one-flowered inflorescences at their apex. The usually short-lived flowers are mainly white (often turning reddish when they start wilting), with mostly very narrow, pointed sepals and petals. A few species deviate in that they have more substantial flowers with attractive colours, such as Diplocaulobium regale, Diplocaulobium auricolor and Diplocaulobium centrale. These rank among the finest orchids of New Guinea. Diplocaulobium is closely related to Dendrobium, and was included in it by both Schlechter and J.J. Smith.