Accepted name: Dendrochilum perplexum (Ames) L.O.Williams, Philipp. J. Sci. 80: 299 (1952)

 

 

Accepted name: Dendrochilum perplexum var. montanum (Ames) H.A.Pedersen, Opera Bot. 130: 20 (1997)

 


Subgenus – Acoridium. Section – Acoridium.


 
 

Synonyms

 

var. perplexum

 

Acoridium perplexum Ames, Orchidaceae 7: 142 (1922).

 

var. montanum

 

Acoridium montanum Ames, Schedul. Orchid. 5: 1 (1923).

Dendrochilum montanum (Ames) L.O.Williams, Philipp. J. Sci. 80: 399 (1952).

Acoridium linearifolium Ames, Orchidaceae 7: 141 (1922), nom. illeg.

 

Origin in the Wild

 

Luzon

 

Elevation in the Wild

 

var. perplexum

 

1830 metres

 

var. montanum

 

1830-2450 metres

 

Habitat in the Wild

 

var. perplexum

 

This species has been found growing as an epiphyte in mossy forest. Specimens have been collected from Benguet Province on Mount Sinapsapan and in Ifugao Province on Mount Himi-o.

 

var. montanum

 

This species has been collected from Benguet Province on Mount Boadan and on Mount Pauai. This species grows as an epiphyte in mossy forest. Ramos specimen was noted as growing on a tree in mossy forest.

 

The Plants Description

 

var. perplexum

 

This Dendrochilum is tufted and grass-like. The pseudobulbs cluster together on a short rhizome and are shaped terete to fusiform. The pseudobulbs measure 3.7-10.0cm long. The pseudobulbs are covered by 5-6 cataphylls while they are growing. The cataphylls disintegrate into persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 2.9-13cm long. The leaf blades are dorsiventrally complanate, shaped narrowly linear and have acute apices. The leaf blades measure 29.5-48cm long and 0.2-0.3cm wide. The leaves have 1-3 distinct nerves, the two lateral nerves, if present are 0.5mm from the margin.

 

var. montanum

 

This Dendrochilum is tufted and grass-like. The pseudobulbs cluster together on a short rhizome and are shaped terete. The pseudobulbs measure 3.0-7.8cm long. The pseudobulbs are covered by 4-5 cataphylls while they are growing. The cataphylls disintegrate into persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 3.8-9.5cm long. The leaf blades are dorsiventrally complanate and shaped narrowly linear with acute apices. The leaf blades measure 16.9-26.5cm long and 0.2-0.3cm wide. The leaves have 1-3 distinct nerves, the two lateral nerves, if present are 0.5mm from the margin.

 

The Inflorescence

 

var. perplexum

 

The peduncle is enclosed for most of its length by the subtending leaf and appears to grow from its distal section. The peduncle measures 20-31.5cm long. The rachis measures 3.2-4.7cm long. The flowers alternate distichously and are spaced 2-3mm apart. There are 2-4 appressed non-floriferous bracts at the base of the rachis. The flowers open from the central section of the rachis.

 

var. montanum

 

The peduncle is enclosed for most of its length by the subtending leaf and appears to grow from its distal section. The peduncle measures 18.5-26.5cm long. The rachis is probably pendent and measures 7.2-9.4cm long. The flowers alternate distichously and are spaced 2-3mm apart. There are 2-3 appressed non-floriferous bracts at the base of the rachis. The sequence of flowering is not known but on variety perplexum it is from the centre of the rachis.

 

The Flowers

 

var. perplexum

 

Henrik Pedersen wrote that the flowers are white or red. Ames wrote that the flowers are red. The sepals and petals open widely. The dorsal sepal is shaped lanceolate and has an acuminate apex. The dorsal sepal measures 4.5-5.1mm long and 1.3-1.5mm wide. The dorsal sepal has an entire margin, is three veined and glabrous. The lateral sepals are shaped oblique, lanceolate to narrowly ovate-lanceolate and have acute-acuminate apices. The lateral sepals measure 4.5-5.7mm long and 1.5-1.9mm wide. The lateral sepals have entire margins, are three veined and glabrous. The petals are shaped elliptic to lanceolate and have acuminate apices. The petals measure 3.8-4.7mm long and 1.5-1.9mm wide. The petals have entire margins, are three veined and glabrous. The labellum is porrect, 3-lobed and one veined. The side lobes are erect, shaped obliquely oblong and have rounded apices. The side lobes distinctly exceed the mid-lobe and are somewhat auriculate at their base. The mid lobe is shaped subquadrate and has a rounded-truncate apex, apiculate in its centre. The margins on the labellum are entire. There are two lateral calli located at the base of each side lobe and appear to point at the side lobe. The median callus is located at the proximal centre of the disc.  The column is erect, nearly straight and measures 0.8-0.9mm long. The column is somewhat hooded at its apex. The anther cap is suborbicular from its upper view and rounded from its front.

 

var. montanum

 

Henrik Pedersen wrote that the flowers are white. The sepals and petals open widely. The dorsal sepal is shaped lanceolate and has a subacute apex. The dorsal sepal measures 5.2-5.4mm long and 1.3-1.4mm wide. The dorsal sepal has an entire margin, is three veined and glabrous. The lateral sepals are shaped oblique, broadly lanceolate and have acuminate apices. The lateral sepals measure 5.9-6.2mm long and c1.9mm wide. The laterals have entire margins, are three veined and glabrous. The petals are shaped lanceolate and have acute apices. The petals measure 4.9-5.0mm long and 1.2-1.3mm wide. The petals have entire margins, are three veined and glabrous. The labellum is porrect 3-lobed and one veined. The side lobes are erect, shaped obliquely oblong and have rounded apices. The side lobes are equal to or slightly exceed the mid-lobe and are somewhat auriculate at their base. The mid lobe is shaped subquadrate and has a truncate apex, slightly apiculate in its centre. The margins on the labellum are entire. There are two lateral calli located at the base of each side lobe and appear to point to the apex of the mid-lobe. The median callus is located proximally in the centre of the disc.  The column is erect, nearly straight and measures 1.2-1.3 mm long. The column is somewhat hooded at its apex. The anther cap is broadly elliptic from its upper view and rounded from its front.

 

Herbarium Specimens

 

Holotype

 

AMES


Specimen 18830 (photo)

Specimen 47 (photo)

Specimen 926 (photo)

Specimen 877 (photo) (Acoridium linearifolium) (var. montanum)

 

 

Isotype

 

New York Botanical Garden (NY)

 

Specimen 39527

Specimen 39535 (Acoridium linearifolium) (var. montanum)

 

AMES

 

Specimen 35 (photo) (Acoridium linearifolium) (var. montanum)

 

 

Other herbarium specimens

 

BM

 

Royal Botanic Gardens, Kew (K)

 

I could not locate the specimen

 

P

 

SING

 

US

 

W

 

AMES

 

Specimen 926 (photo)

 

Scent

 

I could find no record

 

Flowering Season

 

var. perplexum

 

Flowering plants have been collected in the wild during April and October and possibly September.

 

var. montanum

 

Flowering plants have been collected in the wild during September.

 

Culture

 

I do not think this species is in cultivation

 

Similar Species

 

Dendrochilum graminifolium

Dendrochilum stenophyllum

Dendrochilum louisianum

 

Other Information

 

When Ames described Acoridium perplexum he wrote that this species was similar to Acoridium graminifolium.  Ames wrote that Acoridium perplexum differed from D. graminifolium by its inflorescence, longer leaves and flower colour. Ames wrote that Acoridium linearifolium (Dendrochilum perplexum var. montanum) and this species were so similar that it was difficult to separate them from dried material. Ames wrote that the most distinguishable feature was the lateral lobes of Acoridium perplexum which distinctly exceed the mid-lobe. Ames mentioned that the mid-lobe on Acoridium perplexum was concave and distinguishable from Acoridium linearifolium.

 

Ames and L.O Williams considered Dendrochilum perplexum and Dendrochilum montanum to be two separate species but very similar. The only differences given were the length of the labellum mid-lobe, the shape of the lateral calli and the direction the lateral calli were pointed. For this reason Henrik Pedersen made them both varieties and Dendrochilum perplexum had priority as a name.

 

Henrik Pedersen wrote that this species is allied to Dendrochilum graminifolium, D. stenophyllum and D. louisianum. These species are similar because of their dorsiventrally complanate leaves, a peduncle that is adherent to the subtending leaf at the time of flowering and a labellum with a flat or slightly concave disc.

 

When Ames originally described Acoridium linearifolium he did not realise that that name was already given to a species from Peninsula Malaysia and Sumatra. Ames changed the name to Acoridium montanum during 1923. L.O. Williams changed the name to Dendrochilum montanum in 1952 and wrote that the species was very similar and had a close relationship to Dendrochilum perplexum.

 

Ames and L.O Williams considered Dendrochilum perplexum and Dendrochilum montanum to be two separate species but very similar. The only differences given were the length of the labellum, the shape of the lateral calli and the direction the lateral calli were pointed. For this reason Henrik Pedersen made them both varieties of each other and Dendrochilum perplexum had priority as a name. Pedersen wrote that the other differences such as length of leaves and tepals can not be considered definite as there are very few specimens in herbarium collections.

 

Reference -

 

AMES, Oakes. 1922, Illustrations and studies of the Family Orchidaceae Facsimile 7 Pogonia and its Allies in the North Eastern United States and Other Papers, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.

 

AMES, Oakes. 1923, New and Noteworthy Orchids Central America and the Philippines, Schedulae Orchidianae, No 5. Massachusetts, Boston.

 

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

 

World Checklist of Selected Plant Families. 31 December 2008. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 31 December 2008.