Dendrobium speciosum complex.
Dendrobium speciosum is an Australian native known as the Sydney Rock Orchid.
It occurs over large areas and has been broken into a number of species, subspecies and
varieties collectively known as the Speciosum complex.
The Dendrocoryne section of the dendrobiums includes species such as D. gracilicaule,
D. kingianum (the Pink Rock Orchid) and the speciosum complex with D. speciosum
varieties such as D. hillii, D. grandiflorum, D. curvicaule and D. pedunculatum.
Natural hybrids include D. X ruppiosum, D. X gracillimum, D. jonesii and D. x gracillimum.
Some are also seen under the genus name of Thelychiton – T. aff. curvicaulis, T. finniganensis and
T. kingianum (syn. include Dendrocoryne kingianum and Thelychiton kingianus).
The orchids are epiphytic on trees or rocks.
They range from dwarf species only a few cms high to huge clumps.
Pseudobulbs, up to 60 cm or more high, have a dense mass of roots.
Stems can be straight or curved, round or slightly flattened, of even thickness or with a
wider section at the base or centre.
There may or may not be aerial roots.
There are 2 to 5 leathery leaves up to 30 cm long.
There is usually only a single, stiff, erect or slightly arched inflorescence, rarely two.
They can have up to 70 or more flowers that may be close or more widely spaced.
Flowers are fleshy, up to 25 to 30 mm across and some open more widely than others.
Colours are white, cream or pale to deep yellow and they may darken with age.
The white lip can have a purple border, or large or small areas, spots or lines in blue, mauve or red.
A large, flowering clump can form a really spectacular display.
J.F.
