Accepted name: Dendrochilum longirachis Ames, Orchidaceae 6: 60 (1920)

Subgenus – Platyclinis. Section – Platyclinis.


 
 

Synonyms

 

None

 

Origin in the Wild

 

Kalimantan, Sabah and Sarawak

 

Elevation in the Wild

 

1100-2200 metres

 

Habitat in the Wild

 

The type specimen was collected on Mount Kinabalu by Clemens on Marai Parai Spur.

 

Within Kalimantan this species has been collected on Apo Kayan.

 

In Sabah most specimens have been collected from Mount Kinabalu; further collections have been made in the Sipitang District along the Pa Sia River.

 

Within Sarawak this species has been collected in the Kelabit highlands on Mount Murud East and in the Belaga District on Mount Dulit along the Upper Koyan River and the headwaters of the Dapur and Belapan Rivers.

 

Jeffrey Wood (2001) described the habitat as forest on sandy floor, riverine lower montane forest with Rhododendron understory, dense primary forest to 30m high and on poor sandy soil over sandstone.

 

The Plants Description

 

The pseudobulbs crowd along a branched rhizome and are shaped cylindrical to narrowly fusiform. The pseudobulbs measure 5-9.5cm long and 0.5-0.7cm in diameter. The pseudobulbs are shiny green. The pseudobulbs are covered by 3-4 cataphylls while they are growing. The cataphylls disintegrate into persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 6-11mm long. The leaf blades are shaped oblong-elliptic to elliptic and have rounded to acute apices. The leaf blades measure 8-15cm long and 3-4.3cm wide. The leaves are thin textured, and have 9 distinct nerves.

 

The Inflorescence

 

The inflorescence is synanthous and is brownish pink. The peduncle is arching and measures 3-8.4cm long. The rachis is quadrangular in cross section, pendent and measures 20-45cm long. The flowers alternate distichously and are spaced 4mm apart. There are 5-9 non-floriferous bracts at the base of the rachis. The bracts are salmon pink.

 

The Flowers


Ames wrote that up to 135 flowers can grow on an inflorescence (Ames 1920). Jeffrey Wood wrote that the sepals and petals are coloured greenish yellow, palest green, translucent yellow, dull greenish cream or white. The labellum is yellow or pale green, the side lobes often white, keels brown and the column pale yellow (Wood 2001). The dorsal sepal is shaped oblong-elliptic and has an acute apex. The dorsal sepal measures 4.5-5.5mm long and 1.5mm wide. The dorsal sepal has an entire margin and is three veined. The lateral sepals are shaped slightly obliquely oblong-elliptic and have acute apices. The lateral sepals measure 4.5-5.6mm long and 1.6-1.7mm wide. The laterals have entire margins and are three veined. The petals are shaped linear-elliptic and have acute apices. The petals measure 4.0-5.5mm long and 1mm wide. The petals are three veined either entire or have minutely erose margins. The labellum is 3-lobed, stipitate to the column foot by a narrow claw, three veined and minutely papillose. The labellum measures 4.5-4.6mm long and 1.8-1.9mm wide. The side lobes are shaped narrowly triangular; there is one setaceous apical portion on each that hangs down. The side lobes measure 1.5-1.6mm long and terminate mid way along the length of the mid-lobe. The margins on the side lobes are entire except for the upper section which is serrate. The mid-lobe is shaped cuneate-obovate and has an apiculate apex. The margins are either erose or entire. There are two keels that emerge from the labellum’s base and terminate at the base of the mid-lobe; the keels are joined basally by a median nerve. The keels are partially papillose. The column is gently incurved and measures 2.5-2.6mm long. The column foot is short. The apical hood is oblong and has a rounded to truncate apex with an entire or obscurely erose margin. The stelidia grow upwards from the middle of the column just below the level of the stigmatic cavity. The stelidia do not reach the column apex but slightly exceed the anther cap. The stelidia measure 1.4-1.5mm long and are shaped linear-subulate with acute apices.

 

Herbarium Specimens

 

Syntype

 

AMES

 

Specimen 48117 (photo)

Specimen 48116 (photo)

 

The AMES herbarium syntypes have the following note “Ames annotated two specimens without designating a holotype”

 

Isotype

BO

 

Royal Botanic Gardens Kew (K)

 

Specimen K000079126 (photo)

 

Other herbarium specimens

 

National Herbarium Netherlands (L)

 

Specimen L0322626

Specimen L0322627

Specimen L0322628

Specimen L0322629

 

SAR

 

Royal Botanic Gardens Kew (K)

 

Specimen 51004.000

Specimen 61475.000

 

SING

 

BO

 

BM

 

E

 

SAN

 

UKMS

 

Scent

 

Yes, a slight sweet scent.

 

Flowering Season

 

Flowering plants have been collected in the wild from September to January and during April and July. Plants on Mount Kinabalu mostly flower from October to January.

 

Culture

 

I do not think this species is in cultivation

 

Similar Species

 

Dendrochilum gracile

Dendrochilum truncatum

Dendrochilum papillosum

Dendrochilum lacteum (see this page for the differences)

 

Other Information

 

The epithet refers to the long rachis.

 

Reference

 

AMES, Oakes. 1920, Illustrations and studies of the Family Orchidaceae Facsimile 6 The Orchids of Mount Kinabalu British North Borneo, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.

 

BEAMAN, Teofila, WOOD, Jeffrey, BEAMAN, Reed, BEAMAN, John. 2001, Orchids of Sarawak, Natural History Publications Borneo, Kota Kinabalu, Malaysia.

 

WOOD, Jeffrey. Dendrochilum of Borneo, 2001. Natural History Publications (Borneo), Malaysia.

 

WOOD, Jeffrey. 2003, Orchids of Borneo volume 4. The Sabah Society, Kota Kinabalu, Malaysia.

 

World Checklist of Selected Plant Families. 16 March 2009. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 16 March 2009.