Accepted name: Dendrochilum asperum L.O.Williams, Philipp. J. Sci. 80: 309 (1952)

Subgenus – Acoridium. Section – Acoridium.

 

The photo above is from Ames 1923

 

 

Synonyms

 

Acoridium exasperatum Ames, Schedul. Orchid. 6: 21 (1923).

 

Origin in the Wild

 

Luzon

 

Elevation in the Wild

 

1200 metres

 

Habitat in the Wild

 

This species has been found in Laguna Province on Mount San Cristobel; in Quezon Province on Mount Camatis and in Rizal on Mount Lumutan.

 

This species has been recorded as an epiphyte of mossy forest (Ames 1923).

 

The Plants Description

 

The pseudobulbs cluster on a short rhizome and are shaped fusiform. The pseudobulbs measure 0.8-2cm long and 0.1-0.2cm in diameter.  The pseudobulbs are covered by 4-5 cataphylls while they are growing. The cataphylls disintegrate into non-persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 0.4-2.2cm long. The leaf blades are shaped linear-lanceolate and have obtuse and sometimes finely mucronate apices. The blades measure 3.1-14.9cm long and 0.3-0.9cm wide. The leaves have 3 distinct nerves; the 2 outermost nerves are 1-1.5mm from the leaf margin.

 

The Inflorescence

 

The inflorescence is synanthous and is free from the subtending leaf at the time of flowering. The peduncle is suberect to curved and measures 3.1-11.2cm long. The rachis is nodding to pendent and measures 1.8-6.2cm long. The flowers are alternate distichously and are spaced 1-2mm apart. There are 1-2 non floriferous bracts. The flowers open from the proximal section of the rachis.

 

The Flowers

 

The flowers are white. The sepals and petals spread widely and are somewhat recurved. The dorsal sepal is shaped oblong-elliptic and has an obtuse apex. The dorsal sepal measures 1.6-2.2mm long and 0.6-1.2mm wide. The dorsal sepal is one veined and has entire margins. The lateral sepals are shaped obliquely elliptic-ovate and have subacuminate apices. The lateral sepals measure 1.7-2.1mm long and 0.7-1.1mm wide. The lateral sepals are one veined and entire margins. The petals are shaped obliquely elliptic and have subacute to subacuminate apices. The petals measure 1.4-1.7mm long and 0.7-1.1mm wide. The petals are one veined and have entire margins. The labellum is porrect, 3-veined and 3-lobed. The labellum measures 0.6-0.9mm long and 1.3-1.7mm wide. The side lobes are erect, shaped falcately oblong to somewhat crescent shaped with obtuse to rounded apices. The side lobes distinctly exceed the mid-lobe. The mid-lobe is shaped transversely oblong and has an up curved apiculum at the centre of the apex. The margins on the labellum are entire. There are 2 lateral calli located at the base of each side lobe, the calli are shaped oblongoid. The median callus is minute and located at the centre of the labellum and close to its base. The column is suberect and measures 0.5-0.7mm long. The column is hooded at its apex. The anther cap is broadly ovate from its upper view and obtuse from its front.

 

Herbarium Specimens

 

Holotype

 

AMES

 

Specimen 31 (photo) (Acoridium exasperatum)

 

Isotype

 

P

 

Other herbarium specimens

 

National Herbarium Netherlands, Leiden (L)

 

Specimen L0269517

 

Scent

 

I could find no record

 

Flowering Season

 

Flowering plants have been collected in the wild during April and May.

 

Culture

 

I do not think this species is in cultivation

 

Similar Species

 

Dendrochilum microchilum

Dendrochilum parvulum var strictiforme

Dendrochilum parvulum var parvulum

Dendrochilum mindanaense

Dendrochilum quadrilobum

Dendrochilum binuangense

 

Dendrochilum curranii

 

Other Information

 

Oakes Ames wrote (1923) that this species was closest to Dendrochilum microchilum but differed because its petals were broadly ovate or elliptic. Ames also wrote that the labellum is similar to Dendrochilum microchilum. In this paper Ames described this species as Acoridium exasperatum (Ames 1923).

 

L.O Williams transferred Acoridium exasperatum to Dendrochilum in 1952. Williams proposed Dendrochilum asperum as its name because Dendrochilum exasperatum was already in use for a species from Borneo. L.O. Williams wrote that Dendrochilum asperum was closely related to Dendrochilum curranii because of an overall resemblance. Henrik Pedersen wrote that the two species can be distinguished by the veining of the sepals and the size and location of the calli. The main difference is the type of leaf, Dendrochilum curranii has convolute leaves and Dendrochilum asperum has conduplicate leaves (Pedersen 1997).

 

Henrik Pedersen grouped this species with the first 6 species mentioned under similar species. They are grouped because of the similarities of the labellum, vegetative similarities and a peduncle that is free from the subtending leaf at the time of flowering.

 

Reference -

 

AMES, Oakes. 1923, New and Noteworthy Orchids, Schedulae Orchidianae, No 6. Massachusetts, Boston.

 

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

 

World Checklist of Selected Plant Families. 04 December 2008. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 04 December 2008.