Accepted name: Dendrochilum williamsii (Ames) Pfitzer in H.G.A.Engler (ed.), Pflanzenr., IV, 50 II B 7: 114 (1907)

Subgenus – Acoridium. Section – Acoridium.




Acoridium williamsii Ames, Proc. Biol. Soc. Wash. 19: 143 (1906).


Origin in the Wild




Elevation in the Wild


1165-2540 metres


Habitat in the Wild


Ames wrote that the type of this species was found at Trinidad in Benguet Province where it was growing on rocks. This species has been collected from the following provinces:


Benguet - La Trinidad, Mount Data, Mount Pauai, Mount Santo-Tomas

Ifugao - Mount Himi-o, Mount Pimmage, Sumigar

Mountain Province - Mount Polis

Rizal - Montalban, Mount Irid, Mount Tokduanbanoy.

Apayao – Mount Sulu


Henrik Pedersen wrote that this species grows as an epiphyte and sometimes lithophyte in mossy forest (Pedersen 1997). Jim Cootes wrote that this plant grows on moss covered branches of trees (Cootes 2001).


The Plants Description


The pseudobulbs cluster along the rhizomes; the pseudobulbs are shaped terete to slenderly terete-fusiform. The pseudobulbs measure 2.2-13.1cm long and 0.1-0.2cm in diameter. 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 sessile. The leaf blades are shaped linear and have acute apices. The leaf blades measure 15.2-40.5cm long and 1mm wide. The leaves are a triangular shape in cross section.


The Inflorescence


The inflorescence emerges with the new growth. The peduncle is suberect to curved and measures 8.5-32cm long. The peduncle is enclosed for most of its length by the subtending leaf and appears to grow from its distal section. The flowers are spaced 1.5-3mm apart and alternate distichously. The rachis is nodding to pendent and measures 2-9cm long. The flowers open from the proximal, central or distal part of the rachis first. The bracts are longer than the ovary.


The Flowers


The flowers are greenish-white, white, greenish-yellow or reddish-salmon (Pedersen 1997). Up to 25 flowers can grow on an inflorescence (Cootes 2001). The dorsal sepal is shaped linear-oblong to broadly oblanceolate and has an obtuse to acuminate apex. The dorsal sepal is narrower than the laterals sepals. The dorsal sepal measures 2-3.7mm long and 0.7-1.3mm wide. The dorsal sepal is three veined and has an entire margin. The lateral sepals are shaped triangular-ovate to elliptic-ovate (Pedersen), ovate-lanceolate (Ames) and have obtuse to acuminate apices. The lateral sepals measure 2-3.7mm long and 1-1.9mm wide. The lateral sepals are three veined and have entire margins. The petals are shaped oblanceolate-oblong to subspathulate and have acuminate to obtuse apices. The petals measure 2-3.2mm long and 0.8-1.4mm wide. The petals are three veined and have entire margins. The labellum is porrect and 3-lobed. The labellum measures 0.8-1.2mm long and 1.4-1.9mm wide. The margins are entire. The side lobes are shaped oblong-falcate and have obtuse apices that exceed the mid-lobe. The mid-lobe is shaped linear-triangular and has a subacute (Pedersen), obtuse (Ames) apex. There are two calli located at the base of each side lobe. The median callus produces a low and median keel on the disc. The column is suberect, straight and measures 0.6-1mm long. The column is slightly hooded at its apex.  The anther cap is broadly ovate-elliptic from its upper view and obtuse from its front.


Herbarium Specimens




New York Botanical Garden (NY)


Specimen 39516 (photo)






Specimen 65 (photo)

Specimen 66 (photo)


Royal Botanic Gardens, Kew (K)


I could not locate the specimen





Other herbarium specimens


National Herbarium Netherlands (L)


Specimen L0322817

Specimen L0322818




Specimen 1062 (Photo) (holotype fragment from NY and drawing)






Flowering Season


Flowering plants have been collected in the wild from September to November and during January. Plants flower in European cultivation during winter and spring. Plants flower in Australian cultivation during the winter (Cootes et al 1995).




This species is in cultivation, I have seen plants in Europe, the United States of America, Australia and Brazil.


Given that this species has been recorded as high as 2500 metres it could be grown very cool with good results. I have not grown this species myself but from listening to others growers experience it should be given plenty of humidity, water and air movement.


Similar Species


Dendrochilum tenellum

Dendrochilum luzonense

Dendrochilum wenzelii (particularly when not in flower)

Dendrochilum graminifolium

Dendrochilum banksii


Other Information


Ames wrote in his Facsimile 2 that this species differs from Dendrochilum tenellum by its stricter habit, thicker and triangular leaves, larger flowers and different shaped labellum. This species was originally described by Ames as Acoridium williamsii in 1906, Ames wrote that the habit of this species is very similar to Dendrochilum tenellum and the flowers opened from the distal section of the rachis.


I do not know what type of rock this species was found growing on.


The epithet refers to R. Williams who collected the type specimen.




AMES, Oakes. 1906, Descriptions of New Species of Acoridium from the Philippines, Proceedings of the Biological Society of Washington, Vol XIX PP. 143-154 September 25, 1906.


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


COOTES, Jim. The Orchids of the Philippines, 2001. Timber Press, USA


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. 15 September 2008. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; accessed 15 September 2008.