Bulbophyllum gracillimum, commonly known as the wispy umbrella orchid,[1] is a species of epiphytic orchid. It has a creeping rhizome, widely spaced, olive green pseudobulbs, each with a single thick, leathery, fleshy leaf and between six and ten purplish red flowers spreading in a semicircular umbel. The flowers have distinctive long, thread-like tails on the lateral sepals. It has a wide distribution and is found in New Guinea, New Caledonia, Indonesia, Malaysia and part of tropical North Queensland.
Bulbophyllum gracillimum is an epiphytic herb that has a creeping rhizome with olive green pseudobulbs NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide well spaced along it. Each pseudobulb has a single thick, leathery, olive green, oblong to narrow egg-shaped leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide on its end. Between six and ten flowers are arranged in a spreading, semi-circular umbel NaNsigfig=2NaNsigfig=2 long. The flowers are purplish red, resupinate, NaNsigfig=2NaNsigfig=2 long and NaNsigfig=2NaNsigfig=2 wide . The dorsal sepal is egg-shaped, about 3sigfig=2NaNsigfig=2 long and 2sigfig=2NaNsigfig=2 wide, forming a hood over the column. There is a long, hair-like tip NaNsigfig=2NaNsigfig=2 long on the dorsal sepal. The lateral sepals are NaNsigfig=2NaNsigfig=2 long, NaNsigfig=2NaNsigfig=2 wide and fused to each other along their sides at the base. The ends of the lateral sepals taper into long, thread-like "tails" NaNsigfig=2NaNsigfig=2 long. The petals droop with long hairs on the tip, NaNsigfig=2NaNsigfig=2 long and about 1sigfig=2NaNsigfig=2 wide . The labellum is white to cream-coloured, fleshy, curved, about 2sigfig=2NaNsigfig=2 long and 1sigfig=1NaNsigfig=1 wide with a groove along its midline. Flowering occurs between August and March in Australia.[2]
The wispy umbrella orchid was first formally described in 1895 by Robert Allen Rolfe and given the name Cirrhopetalum gracillimum. The description was published in the Bulletin of Miscellaneous Information, Royal Gardens, Kew[3] [4] but in 1907 Rolfe changed the name to Bulbophyllum gracillimum.[5] The specific epithet (gracillimum) is a Latin word meaning "slenderest".[6]
Bulbophyllum gracillimum grows on trees in stunted rainforest and in other damp, airy places in Indonesia, Malaysia, New Guinea, New Caledonia, Fiji and Queensland. In Queensland it occurs in the Iron and Janet Ranges at altitudes of NaNsigfig=2NaNsigfig=2.[7]
This orchid is classed as "vulnerable" under the Australian Government Environment Protection and Biodiversity Conservation Act 1999.[8] The main threat to the species is illegal collecting by orchid enthusiasts.[9]