Accepted name: Dendrochilum gravenhorstii J.J.Sm., Bull. Jard. Bot. Buitenzorg, III, 2: 28 (1920)

Subgenus – Dendrochilum.


 
 

Synonyms

 

None

 

Origin in the Wild

 

Kalimantan, Sabah and Sarawak

 

Elevation in the Wild

 

100-1000 metres

 

Habitat in the Wild

 

The type specimen was collected in Kalimantan Barat, Upper Kapuas in the Talaj River area. Further collections have been made from Sarawak, Marudi District on the route to Pa Ukat, Bario area and along the Sipiyang River in the Limbang District. In Sabah this species has been collected from Sandakan District at the Telupid Hap Seng logging area and near the Nabawan old airstrip.

 

Jeffrey Wood described the habitat as kerangas forest and podsolic dipterocarp forest on steep slopes and wet sandy soil (Wood 2001).

 

The Plants Description

 

This species is a terrestrial or epiphyte. The rhizome can grow to 40cm; the pseudobulbs are spaced 1.3-4.5cm apart along it and grow at an acute angle. The pseudobulbs are shaped obliquely oblong-ovoid and measure 1.3-2.5cm long and 0.55-0.75cm in diameter. The pseudobulbs are pale green or ochre colour. The pseudobulbs are covered by 4-6 cataphylls while they are growing. The cataphylls disintegrate into non-persistent fibres as the pseudobulbs mature. The cataphylls are a glossy chestnut-brown colour and are sometimes speckled. The leaves are petiolate, the petiole measures 2-3mm long. The leaf blades are shaped linear, ligulate and have obtuse to acute apices. The leaf blades measure 4.5-11.5cm long and 0.5-0.8cm wide. The leaves have 5 distinct nerves.

 

The Inflorescence

 

The inflorescence is heteranthous. The peduncle is erect and measures 1-2cm long. The rachis is arching to arcuate and measures 5-8cm long. The rachis is quadrangular in cross-section. The flowers alternate distichously and are spaced 2-3mm apart. The flowers open from the proximal section of the rachis.

 

The Flowers

 

The flowers are pale green to pale yellow, the labellum is yellowish-green with a white margin, and the stelidia are white. The dorsal sepal is shaped narrowly oblong and has an apiculate apex. The dorsal sepal measures 4.4-4.5mm long and 1.3mm wide. The dorsal sepal has an entire margin and is three veined. The lateral sepals are shaped obliquely oblong-ovate, somewhat subfalcate and have acute apices. The lateral sepals have entire margins and are three veined. The laterals measure 4mm long and 1.6mm wide. The petals are shaped obliquely lanceolate to linear-lanceolate and have acute apices. The petals have entire margins and are one veined. The petals measure 3.7mm long and 0.8mm wide. The labellum is three veined and subentire, decurved with an apex often recurved. The labellum measures 2.7mm long and 1.25mm wide. The labellum is shaped lanceolate and has an acute apex. The margins on the labellum are mostly entire, but are erose on the hypochile with a few teeth at its base. There are 3 keels that emerge from the base of the hypochile, the median keel is shorter. The column is gently curved and measures 2mm long. The apical hood is shaped quadrangular and the margin is 2-4 dentate. The stelidia grow from just below the middle of the column, are shaped linear-ligulate and have acute apices.

 

Herbarium Specimens

 

Holotype

 

BO

 

 

Isotype

 

National Herbarium Netherlands Leiden (L)

 

Specimen L0056508 (photo)

 

 

Other herbarium specimens

 

Royal Botanic Gardens Kew (K)

 

Specimen 60700.000

Specimen K000078151

Specimen K000078152

Specimen K000078150

Specimen K000078153

Specimen K000078154 (drawing)

 

 

National Herbarium Netherlands Leiden (L)

 

Specimen L0322530

Specimen L0322531

 

AAU

 

MEL

 

SAR

 

SING

 

KEP

 

Scent

 

Yes, sweetly scented.

 

Flowering Season

 

Flowering plants have been collected in the wild during June and July.

 

Culture

 

I do not think this species is in cultivation.

 

Similar Species

 

Dendrochilum crassum

Dendrochilum pallidiflavens

 

Other Information

 

Jeffrey Wood wrote that this species is distinguished by other similar species by its ornate labellum. Wood wrote that the ornaments on the labellum have a more complicated structure than others within the subgenus Dendrochilum (Wood 2003).

 

The epithet refers to C.A. Gravenhorst of a Danish oil laboratory. Gravenhorst went to Borneo to investigate plants with oily seeds.

 

Reference

 

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. 09 January 2009. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 09 January 2009.