Accepted name: Dendrochilum irigense Ames, Orchidaceae 5: 58 (1915).

Subgenus – Acoridium. Section – Convoluta.


 

Synonyms

 

Acoridium irigense (Ames) Ames, Orchidaceae 7: 81 (1922).

 

Origin in the Wild

 

Luzon

 

Elevation in the Wild

 

500-1665 metres

 

Habitat in the Wild

 

The species has been recorded growing as an epiphyte on Mount Iriga and Mount Isarog in Camarines Sur Province. This species has also been collected on Mount Maquiling in Laguna Province.

 

The Plants Description

 

The pseudobulbs cluster on a short rhizome and are shaped slenderly fusiform-terete. The pseudobulbs measure 0.9-5.5cm long and 0.2-0.4cm diameter. The pseudobulbs are covered by 4-5 cataphylls while they are growing. The cataphylls soon disintegrate into persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 0.5-2.5cm long. The leaf blades are shaped lanceolate to linear-lanceolate and have acute apices. The leaf blades measure 2.9-12.4cm long and 0.5-2.0cm wide. The leaves are thin textured with 3-5 distinct nerves on the blade; the 2 outermost nerves c1mm from the leaf margin.

 

The Inflorescence

 

The inflorescence is synanthous and begins to open its flowers while the leaf is still growing. The peduncle is suberect and measures 2.4-6.0cm long. The rachis is nodding and measures 3.1-6.5cm long. The flowers alternate distichously and are spaced 3-5mm apart. There is 1 appressed non-floriferous bract at the base of the rachis. The flowers open from the distal section of the rachis.

 

The Flowers

 

The Santos specimen (NY39533) describes the flowers as yellow and Ramos described them as white. Ames wrote that the flowers brownish-red when they are dry (Ames 1915). Henrik Pedersen wrote that the flowers are white, yellow or green (Pedersen 1997). The sepals and petals spread widely and have a few minute trichomes. The dorsal sepal is shaped oblong and has a rounded-obtuse apex. The dorsal sepal measures 4.9-5.4mm long and 2.1-2.4mm wide. The dorsal sepal is three veined and has an entire margin. The lateral sepals are shaped obliquely elliptic and have obtuse apices. The lateral sepals measure 4.0-5.3mm long and 2.1-2.9mm wide. The lateral sepals are three veined and have entire margins. The petals are shaped obovate-subspathulate and have obtuse apices. The petals measure 4.5-5.7mm long and 2.6-3.4mm wide. The petals are three veined and have entire to slightly irregular margins. The labellum is porrect and 3-lobed. The labellum measures 1.1-1.9mm long and 2.4-2.9mm wide. The labellum is three veined, glabrous and has entire margins. The side lobes are erect, shaped obliquely elliptic-oblong and have obtuse apices. The side lobes are equal in length to the mid-lobe. The mid-lobe is shaped semiorbicular-reniform and has an acuminate apex. There are three calli, the lateral calli are prominent, conical shaped and located at the base of the side lobes close to the front margin. The median callus is shaped oblongoid and is located at the centre of the hypochile. The column is erect and measures 0.9-1.6mm long. The column is hooded at its apex. Stelidia and column foot are absent

 

Herbarium Specimens

 

Lectotype

 

AMES

 

Specimen 18836 (photo)

Specimen 98769 (drawing of the type)

 

Isolectotype

 

AMES

 

Specimen 18837 (photo)

 

Syntype

 

AMES

 

Specimen 18835

 

Isotype

 

New York Botanical Garden (NY)

 

Specimen - 39533

 

Other herbarium specimens

 

BM

 

BO

 

Royal Botanic Gardens, Kew (K)

 

I could not locate the specimen

 

P

 

SING

 

US

 

W

 

Scent

 

I could find no record.

 

Flowering Season

 

Flowering plants have been collected in the wild during December.

 

Culture

 

I only know of this species being cultivated in the United States of America.

 

Similar Species

 

Dendrochilum hutchinsonianum

Dendrochilum affine

Dendrochilum pumilum

Dendrochilum mindorense

Dendrochilum longibulbum

 

Other Information

 

Ames wrote in 1915 that this plant is similar to Dendrochilum hutchinsonianum but differs by the shape of the labellum which Ames likened its shape to Dendrochilum affine. Ames wrote that the flowers are larger than Dendrochilum affine and Dendrochilum pumilum. Ames wrote that this is a variable species in the size of the leaves and pseudobulbs. L.O. Williams also considered this species to be close to Dendrochilum anfractum, now considered to be in a separate subgenus because of its bilobed rostellum.

 

Henrik Pedersen considered this species to be in a group with Dendrochilum affine and Dendrochilum mindorense.

 

Reference

 

AMES, Oakes. 1915, Illustrations and studies of the Family Orchidaceae Facsimile 5, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.

 

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

 

World Checklist of Selected Plant Families. 25 January 2009. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 25 January 2009.