Dendrobium speciosum
Encyclopedia
Dendrobium speciosum is not only a widespread Australian orchid but also a very variable orchid, forming a species complex
. Its varieties can be found in wildly varying habitats as an epiphyte
(on branches of rainforest trees) or a lithophyte
(on sandstone in open forest) in a continuous distribution along the east coast of Australia and in distinct populations along the Tropic of Capricorn
. As a lithophyte, it forms gigantic clumps on rocks and cliff faces with its roots forming dense, matted beds across the rock. It can be found from sea level to mountain tops.
This orchid is popular in cultivation. It is known under several common names : Outstanding Dendrobium, King Orchid, and the somewhat misleading Rock Lily. It was originally named by Sir James Edward Smith
(1759–1828) from a specimen found at Port Jackson
and sent to him by Surgeon General J White.
There are two to five thick, leathery leaves originating from the top of each pseudobulb
. These leaves can remain on the plant for up to 12 years. The erect or curved pseudobulbs are rather large, up to 45 cm long. They are thickest at their base (5 to 7 cm), and often taper towards the apex (3 cm). The showy flowers grow in long raceme
s on straight or slowly arching, long, starchy stems with over 100 flowers per stem from August to October. Their colour varies from white to creamy yellow. The white labellum
is covered with purple dots and veined with red and purple. The roasted stems are edible
Synonyms, based on the same type, include :
Dendrobium speciosum is a single variable species, forming a species complex overlapping in a continuum of variations. The following varieties, based on morphological data, have been proposed by Adams et al. (2006)
with two new varieties :
Some plants at the distribution limits especially of var. hillii do not fit a strict varietal description and are best designated by geographical location. Furthermore, all varieties are susceptible to cross pollination, giving rise to intervarietal seeds.
This species complex has been previously described by Dockrill in 1969 and reviewed by several authors (Clemesha 1981a, 1981b, 1986, Clements 1989, Banks & Clemesha 1990 and Adams 1991 )
Dendrobium speciosum forms a natural hybrid with Dendrobium gracilicaule : Dendrobium × gracillimum. This hybrid has also been described as Dendrobium speciosum var. nitidum F.M.Bailey, , Dendrobium × nitidum (F.M.Bailey) M.A.Clem. & D.L.Jones , Dendrobium speciosum var. bancroftianum Rchb.f. and Dendrobium jonesii Rendle subsp. bancroftianum (Rchb.f.) M.A.Clem. & D.L.Jones .
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
. Its varieties can be found in wildly varying habitats as an epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
(on branches of rainforest trees) or a lithophyte
Lithophyte
Lithophytes are a type of plant that grows in or on rocks. Lithophytes feed off moss, nutrients in rain water, litter, and even their own dead tissue....
(on sandstone in open forest) in a continuous distribution along the east coast of Australia and in distinct populations along the Tropic of Capricorn
Tropic of Capricorn
The Tropic of Capricorn, or Southern tropic, marks the most southerly latitude on the Earth at which the Sun can be directly overhead. This event occurs at the December solstice, when the southern hemisphere is tilted towards the Sun to its maximum extent.Tropic of Capricorn is one of the five...
. As a lithophyte, it forms gigantic clumps on rocks and cliff faces with its roots forming dense, matted beds across the rock. It can be found from sea level to mountain tops.
This orchid is popular in cultivation. It is known under several common names : Outstanding Dendrobium, King Orchid, and the somewhat misleading Rock Lily. It was originally named by Sir James Edward Smith
James Edward Smith
Sir James Edward Smith was an English botanist and founder of the Linnean Society.Smith was born in Norwich in 1759, the son of a wealthy wool merchant. He displayed a precocious interest in the natural world...
(1759–1828) from a specimen found at Port Jackson
Port Jackson
Port Jackson, containing Sydney Harbour, is the natural harbour of Sydney, Australia. It is known for its beauty, and in particular, as the location of the Sydney Opera House and Sydney Harbour Bridge...
and sent to him by Surgeon General J White.
There are two to five thick, leathery leaves originating from the top of each pseudobulb
Pseudobulb
The pseudobulb is a storage organ derived from the part of a stem between two leaf nodes.It applies to the orchid family , specifically certain groups of epiphytic orchids, and may be single or composed of several internodes with evergreen or deciduous leaves along its length.In some species, it is...
. These leaves can remain on the plant for up to 12 years. The erect or curved pseudobulbs are rather large, up to 45 cm long. They are thickest at their base (5 to 7 cm), and often taper towards the apex (3 cm). The showy flowers grow in long raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
s on straight or slowly arching, long, starchy stems with over 100 flowers per stem from August to October. Their colour varies from white to creamy yellow. The white labellum
Labellum
Labellum is the Latin diminutive of labium, meaning lip. These are anatomical terms used descriptively in biology, for example in Entomology and botany.-Botany:...
is covered with purple dots and veined with red and purple. The roasted stems are edible
Synonyms, based on the same type, include :
- Callista speciosa (Sm.) Kuntze,(1891).
- Dendrobium speciosum var. typicum Domin (1915) , nom. inval.
- Dendrocoryne speciosum (Sm.) Brieger(1981)
- Tropilis speciosa (Sm.) Butzin (1982)
- Thelychiton speciosus (Sm.) M.A.Clem. & D.L.Jones (2002)
Dendrobium speciosum is a single variable species, forming a species complex overlapping in a continuum of variations. The following varieties, based on morphological data, have been proposed by Adams et al. (2006)
- Dendrobium speciosum var. speciosum SmJames Edward SmithSir James Edward Smith was an English botanist and founder of the Linnean Society.Smith was born in Norwich in 1759, the son of a wealthy wool merchant. He displayed a precocious interest in the natural world...
, 1804 - Dendrobium speciosum var. hillii Mast., 1877
- Dendrobium speciosum var. grandiflorum F.M.Bailey, 1896 (also lithophytic)
- Dendrobium speciosum var. curvicaule F.M.Bailey, 1896
- Dendrobium speciosum var; pedunculatum Clemesha, 1981
- Dendrobium speciosum var. capricornicum Clemesha, 1982 (also lithophytic)
- Dendrobium speciosum var. boreale P.B.Adams, J.M.Burke & S.D.Lawson, 2006
with two new varieties :
- Dendrobium speciosum Sm. var. blackdownense P. B.Adams var. nov.
- Dendrobium speciosum Sm. var. carnarvonense P. B.Adams var. nov.
Some plants at the distribution limits especially of var. hillii do not fit a strict varietal description and are best designated by geographical location. Furthermore, all varieties are susceptible to cross pollination, giving rise to intervarietal seeds.
This species complex has been previously described by Dockrill in 1969 and reviewed by several authors (Clemesha 1981a, 1981b, 1986, Clements 1989, Banks & Clemesha 1990 and Adams 1991 )
Dendrobium speciosum forms a natural hybrid with Dendrobium gracilicaule : Dendrobium × gracillimum. This hybrid has also been described as Dendrobium speciosum var. nitidum F.M.Bailey, , Dendrobium × nitidum (F.M.Bailey) M.A.Clem. & D.L.Jones , Dendrobium speciosum var. bancroftianum Rchb.f. and Dendrobium jonesii Rendle subsp. bancroftianum (Rchb.f.) M.A.Clem. & D.L.Jones .