Accepted name: Dendrochilum arachnites Rchb.f., Gard. Chron. 1882(1): 256 (1882)

Subgenus – Platyclinis. Section – Platyclinis.


 
 

 

Synonyms

 

Acoridium arachnites (Rchb.f.) Rolfe, Orchid Rev.: 219 (1904).

 

Origin in the Wild

 

Luzon, Leyte, Mindanao and Mindoro

 

Elevation in the Wild

 

500-2600 metres

 

Habitat in the Wild

 

On Luzon this species has been collected on Mount Nangaoto, Mount Natoo, Mount Pangualitikai, Mount Pulog, Mount Santo Tomas, Pauai and Apunan in Benguet Province. In Ifugao Province this species has been found on Mount Batwag and Mount Polis. In Mountain Province it has been collected along the Bontoc Road. Within Pampanga Province it has only been collected on Mount Arayat and in Quezon Province on Mount Banahao. In Rizal Province this species has been collected on Montalban, Mount Susongdalaga and at San Isidro near Bosoboso.

 

On Mindoro this species has been collected on Mount Halcon.

 

On the Island of Leyte in the Visayas this species has been collected at Buenavista and Masaganap both near Jaro.

 

On Mindanao this species has been collected from Agusan del Norte on Mount Urdaneta and from Bukidnon Province on Mount Lipa. In Davao del Norte this plant has been collected on Mount Kampalili and in Davao del Sur on Mount Apo. In Misamis Province this plant has been collected on Mount Malindang.

 

This species is frequently found growing as an epiphyte in mossy forest and in bright light (Cootes 2001, Pedersen 1997).

 

The Plants Description

 

The pseudobulbs grow along an elongate rhizome and can be spaced up to 5.0cm apart. The pseudobulbs are shaped fusiform, ellipsoid to ovoid. The pseudobulbs measure 1.7-5.5cm long and 0.3-1.5cm in diameter. The pseudobulbs are covered by 4-6 cataphylls while they are growing. The cataphylls soon disintegrate into immediately decaying fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 0.7-5.0cm long. The leaf blades are shaped lanceolate to elliptic or ovate and have acuminate apices. The blades measure 4.5-21.5cm long and 2.5cm wide. The leaves are thin textured and have 7-9 distinct nerves.

 

The Inflorescence

 

The inflorescence is synanthous. The peduncle is suberect to curved and measures 4.2-23.0cm long. The rachis is nodding to pendent and measures 2.9-14.1cm long. The flowers alternate distichously and are spaced 3.0-5.0mm apart. There are one or no appressed non-floriferous bracts at the base of the rachis. The flowers open from the proximal or central section of the rachis.

 

The Flowers

 

The flower colour in my experience is a very pale yellow-green. Up to 30 flowers grow on an inflorescence (Cootes 2001). Henrik Pedersen wrote (1997) that the colour can be white to green or yellow and the labellum is greenish white or orange to pale pink. The sepals and petals spread widely are glabrous or have a few minute scattered trichomes. The dorsal sepal is shaped linear, narrowing gradually from the base to the acute or acuminate apex. The dorsal sepal measures 10.5-17.9mm long and 1.6-2.8mm wide. The dorsal sepal is three veined and has entire margins. The lateral sepals are sometimes carinate and shaped linear, narrowing gradually from the base to their acute or acuminate apices. The lateral sepals measure 11.6-18.9mm long and 1.7-3.4mm wide. The lateral sepals are three veined and have entire margins. The petals are shaped narrowly lanceolate narrowing gradually from the base to their acute or acuminate apices. The petals measure 7.4-11.4mm long and 1.2-2.9mm wide. The petals are three veined and have entire margins. The labellum is easily versatile, pendent and entire. The labellum measures 2.7-5.0mm long and 1.1-2.8mm wide. The labellum is shaped oblong and has an obtuse apex. The labellum is three veined and has entire margins. There are no ornaments but is often swollen basally. The column is suberect, straight to slightly incurved and measures 2.0-4.5mm long. The apical hood is prolonged into a rounded and slightly irregular to dentate apex which distinctly exceeds the anther cap. The column foot is short. The stelidia grow upwards from the middle of the column and are shorter than the column apex. The stelidia are shaped falcately linear and have subacute apices. Rarely the stelidia are bidentate.

 

Herbarium Specimens

 

Holotype

 

Herbarium Reichenbach

 

Isotype

 

NA

 

Other herbarium specimens

 

Kew Botanical Gardens (K)

 

Specimen 71187.000

Specimen 20279.000

Specimen 61477.000

 

Scent

 

Yes and no, certain descriptions suggest a faint sweet or cinnamon scent. I haven't detected a scent on this species. Henrik Pedersen also wrote (1997) that the flower can be odourless which my own experience is. Oakes Ames wrote that the flower was odourless (Ames 1907).

 

Flowering Season

 

Flowering plants have been collected in the wild year round except during August. I have experienced cultivated plants flowering during spring in the northern hemisphere. Plants flower during the winter in Australia (Cootes et al 1995).

 

Culture

 

This species is in cultivation around the world I have seen plants in Australia, the European Union, the USA and the Philippines.

 

The plant can be a rambler and should be planted in a bigger pot. This plant does not like disturbance and from my experience is sensitive to water quality.

 

Similar Species

 

Dendrochilum merrillii (please see this page for the differences)

Dendrochilum odoratum

 

Other Information

 

Ames wrote that the leaves on cultivated plants depauperate making the leaves look different from how they would in the wild (Ames 1907).

 

This plant is very often confused with Dendrochilum wenzelii. I have seen Dendrochilum wenzelii sold, pictured and grown as Dendrochilum arachnites 'red'. Dendrochilum arachnites does not have long sharp needle like leaves but defined pseudobulbs with wider paler green leaves. The flowers of Dendrochilum arachnites are bigger, have longer tepals and the flower colour is a very pale yellow-green. Dendrochilum arachnites 'red' form is always Dendrochilum wenzelii and Dendrochilum arachnites 'yellow' is always Dendrochilum javierii. Philippine orchid nurseries export Dendrochilum javierii and Dendrochilum wenzelii incorrectly labelled as Dendrochilum arachnites, unfortunately even some herbarium specimens are incorrectly labelled.

 

The epithet refers to the spider like appearance of the flowers.

 

Reference -

 

AMES, Oakes. 1907, Orchidaceae Halconenses: An Enumeration of the Orchids Collected on and Near Mount Halcon, Mindoro, Chiefly By E.D. Merrill, Bureau of Printing, Manila.

 

COOTES, Jim. The Orchids of the Philippines, 2001. Timber Press, USA

 

COOTES, Jim. BANKS, David. 1995, The genus Dendrochilum A guide to the species in cultivation, Orchids Australia, AOC

 

PEDERSEN, Henrik. 1997, The Genus Dendrochilum (Orchidaceae) in the Philippines - A Taxonomic Revision. Opera Botanica, Denmark

 

World Checklist of Selected Plant Families. 08 January 2009. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 08 January 2009.