Accepted name: Dendrochilum louisianum H.A.Pedersen, Nordic J. Bot. 15: 384 (1995 publ. 1996)

Subgenus – Acoridium. Section – Acoridium.


 
 

Synonyms

 

None

 

Origin in the Wild

 

Luzon

 

Elevation in the Wild

 

800 metres

 

Habitat in the Wild

 

This species was recorded growing on the summit of Mount Balatongan, Cagayan Province. The type was found growing on a tree trunk at the summit.

 

The Plants Description

 

The pseudobulbs cluster on a short rhizome. The pseudobulbs are shaped terete, semi-fusiform and measure 2-4.2cm long and 0.2-0.5mm in diameter. The young pseudobulbs are covered by c4 tubular, acute cataphylls that disintegrate into persistent fibres as the pseudobulbs mature. The leaves are petiolate; the petiole measures 1.5-4.8cm. The leaf blades are dorsiventrally complanate, conduplicate and shaped narrowly linear; the apices are boat-shaped and acute. The leaf blade measures 20.5-29.9cm long and 0.4-0.7mm wide. There are 3-5 distinct nerves on the leaf, the 2 outermost nerves are 0.5-1mm from the leaf margin.

 

The Inflorescence

 

The inflorescence is synanthous. The peduncle is suberect and measures 13.9-16.5cm long. The inflorescence is enclosed for up to half the length of the subtending leaf at the time of flowering. The rachis is nodding and measures 6.3-8.0cm long. The flowers are spaced 1-2mm part along the rachis. There are 2-4 non-floriferous bracts at the base of the rachis.

 

The Flowers

 

The flowers can be white or green. The sepals contain a few tiny trichomes. The dorsal sepal is shaped lanceolate and has an acute apex. The dorsal sepal measures 2.7-2.8mm long and c0.9mm wide. The dorsal sepal is three veined and has an entire margin. The lateral sepals are shaped obliquely oblong-lanceolate and have obtuse apices. The lateral sepals measure 2.9-3mm long and 1.1-1.2mm wide. The lateral sepals are three veined and have entire margins. The petals are shaped oblong-lanceolate and have obtuse apices. The petals measure 1.7mm long and c0.6mm wide. The petals are three veined and have entire margins. The labellum is porrect and can be either entire or distinctly 3-lobed. The labellum measures 1.4-1.5mm long and 1-1.3mm wide. The labellum is one veined, glabrous and has entire margins. The side lobes, if present, are erect and shaped falcately oblong, they are shorter (by half) than the mid-lobe. The mid-lobe is triangular and has an acute apex.  There are two calli located at the base of each side lobe, or where they should be, and close to the apical margin. The column measures c0.7mm long and does not have an apical hood beyond the anther cap. Stelidia and column foot are absent.

 

 

Herbarium Specimens

 

Holotype

 

AMES

 

Specimen 90559 (photo)

 

 

Isotype

 

AMES

 

Specimen 90557 (photo)

 

New York herbarium (NY)

 

I could not locate the specimen

 

Philippine National Herbarium (PNH)

 

Specimen - destroyed

 

Scent

 

I could find no record

 

Flowering Season

 

The specimen at AMES (90559) was collected in the wild during November.

 

Culture

 

I do not think this species is in cultivation. There is a chance that this species could be in cultivation, unknowingly, labelled as Dendrochilum stenophyllum.

 

Similar species

 

Dendrochilum graminifolium

Dendrochilum perplexum var. montanum

Dendrochilum perplexum var. perplexum

Dendrochilum stenophyllum

 

Additional Comments

 

This species is closely related to Dendrochilum stenophyllum but differs by its petals that are smaller than the sepals, shorter side-lobes on the labellum and a longer acute mid-lobe.

 

The epithet is names after Louis Williams who first commented that the specimen at AMES should be a separate species.

 

Reference

 

PEDERSEN, Henrik. 1995, Thirteen new species of Dendrochilum (Orchidaceae), a new record from Burma, and a checklist of the genus in East Malesia. Nord. J. Bot 15:381-402. Copenhagen, Denmark.

 

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

 

World Checklist of Selected Plant Families. 01 September 2008. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 01 September 2008.