Accepted name: Dendrochilum magnum Rchb.f. in W.G.Walpers, Ann. Bot. Syst. 6: 240 (1861).

Subgenus – Platyclinis. Section – Platyclinis.


 
 

Synonyms

 

Acoridium magnum (Rchb.f.) Rolfe, Orchid Rev. 12: 220 (1904).

 

Origin in the Wild

 

Luzon, Mindoro and Mindanao

 

Elevation in the Wild

 

665-1995 metres

 

Habitat in the Wild

 

E.D. Merrill collected this plant growing as an epiphyte in mossy forest on Mount Halcon in Mindoro. H.M. Curran collected this plant from the Lamao Forest Reserve in Benguet Province.

 

This species has been collected on the island of Luzon in Camarines Sur on Mount Isarog and in Sorsogon on Mount Dulangau.

 

On Mindoro this species has been collected on Mount Halcon and Mount Ilong.

 

Within the Visyas Isalnds this species has been collected on Antique near Culasi and on Mount Madia-as; on Negros on Mount Malbug

 

On Mindanao this species has been collected on Mount Apo

 

The Plants Description

 

The pseudobulbs cluster on a short rhizome and are shaped slenderly obpyriform to somewhat fusiform. The pseudobulbs measure 1.8-6.2cm long and 0.4-1.1cm in diameter. The pseudobulbs are covered by 4-5 cataphylls while they are growing. The cataphylls are already torn at the time of flowering and disintegrate into persistent as the pseudobulbs mature. The leaves are petiolate, the petiole measures 7.1-20.5cm long. The leaf blades measure 12.5-40.2cm long and 2.2-6.4cm wide. The leaf blades are shaped lanceolate to linear-lanceolate and have obtuse to acuminate or acute apices. The leaves are thin textured and have 7-9 distinct nerves.

 

The Inflorescence

 

The inflorescence is synanthous. The peduncle is suberect and measures 14.0-38.5cm long. The rachis is pendent and measures 11.5-30.0cm long. The flowers alternate distichously and are spaced 3.5-4.5mm apart. The rachis is glabrous or sparsely and finely setose. There are 2-4 appressed non-floriferous bracts at the base of the rachis. The flowers open from the proximal section of the rachis.

 

The Flowers

 

The flower is usually greenish-white but can be pale shades of green, yellow or brown. The labellum is a rusty brown colour (Pedersen 1997). Ames (1908) described the flower colour as yellowish-green with a brown labellum. The sepals and petals spread widely and sometimes have a few minute trichomes. The dorsal sepal is shaped linear to lanceolate and has an acute to a more or less acuminate apex. The dorsal sepal measures 8.7-11.0mm long and 2.2-3.3mm wide. The dorsal sepal is three veined (rarely five veined) and has entire margins. The lateral sepals are shaped lanceolate to narrowly linear-lanceolate and have acute to somewhat acuminate apices. The laterals measure 8.7-11.3mm long and 2.8-3.9mm wide. The lateral sepals are three veined (rarely five veined) and have entire margins. The lateral sepals can have a few minute trichomes. The petals are shaped lanceolate to elliptic and have acute to somewhat acuminate apices. The petals measure 8.0-9.3mm long and 2.4-3.9mm wide. The petals are 3-5 veined and have erose margins. The labellum is easily versatile, more or less porrect and 3-lobed with a somewhat cymbiform conformation. The labellum measures 2.9-5.8mm long and 1.8-4.8mm wide. The labellum is obscurely three veined and has erose to serrate-fimbriate margins from the base to the apices of the side lobes, the mid-lobe margin is finely erose-crenate to nearly entire. The side lobes are erect, shaped subtriangular and have acute apices. The mid-lobe is shaped suborbicular to elliptic or subquadrate with a rounded apex. There is an obtuse apiculum in the centre of the mid-lobe’s apex. The labellum is finely papillose. There are two small calli located on the lateral nerves at the base of the mid-lobe. The column is suberect, somewhat incurved and measures 2.9-3.8mm long. The apical wing is prolonged into a rounded to truncate apex and has a 3-8 dentate margin. The apical wing distinctly exceeds the anther cap. The stelidia grow upwards from the base of the column and equal the apical wing. The stelidia are shaped linear to linear-lanceolate and have subacute apices.

 

Herbarium Specimens

 

Holotype

 

Royal Botanic Gardens Kew (K)

 

Specimen K000079152 (photo) (Lindley Herbarium)

 

 

Isotype

 

-

 

Other herbarium specimens

 

National Herbarium Netherlands (L)

 

Specimen L0322638

Specimen L0322639

 

Royal Botanic Gardens, Kew (K)

 

Specimen 72545.000

 

AMES

 

Specimen 98782 (drawing of the type)

Specimen 18825 (photo)

 

Scent

 

This species is odourless or has a faint scent (Pedersen 1997). Ames wrote that this species has a faint odour. The Kew specimen, 72545, states that there is a faint rubbery scent.

 

I have read and heard people describe the scent to be like cleaning products or even hay; I have yet to smell a plant like that. This is another Dendrochilum that is often mislabelled so most scent references will be incorrect. I have not flowered this species so I don’t know from my own experience, nearly all plants I have seen labelled as Dendrochilum magnum are in fact Dendrochilum latifolium var macranthum.

 

Flowering Season

 

Flowering plants have been collected in the wild during February and November. Flowering in cultivation generally occurs during autumn, the flowers stay open for about a month.

 

Culture

 

This species is found in cultivation globally, although most often mislabelled. If I see a plant labelled as Dendrochilum magnum is usually assume it is Dendrochilum latifolium var macranthum unless I can see a very good close up of the column and labellum.

 

Similar Species

 

Dendrochilum latifoilum var latifoilum (see this page for the differences)

Dendrochilum latifolium var macranthum (see this page for the differences)

Dendrochilum imbricatum

 

Other Information

 

The photo in Jim Cootes and David Banks 1995 article labelled as Dendrochilum magnum is Dendrochilum latifolium var macranthum. (Pedersen 1997).

 

The Kew specimen has a very good diagram of the flower on it which should help identify it from Dendrochilum latifolium var. macranthum.

 

This species is very often confused with Dendrochilum latifolium var macranthum on internet sites, photos, plant labels and show tables. I have noticed that users on US orchid forums have recently been saying that the two species are synonymous. I do not know where these claims have been substantiated from and I have not seen a published document to back these claims up. I have recently seen a Victorian (Australia) e-bay seller state that Dendrochilum magnum and D. latifolium var macranthum were the same. Sellers in the USA are calling the two species the same; I have contacted one of these sellers to find out why and have not had a response.

 

The key differences between the two species are outlined by Henrik Pedersen (1997), I have copied them below:

 

Dendrochilum magnum. The labellum more or less porrect with a somewhat cymbiform conformation. Column strongly incurved; stelidia subequal to the column proper.

 

Dendrochilum latifolium. Labellum pendent, flat (side lobes often erect). Column slightly incurved; stelidia shorter than the column proper.

 

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.

 

AMES, Oakes. 1908, Illustrations and studies of the Family Orchidaceae Facsimile 2, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.

 

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.